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THE MANUFACTURE 
OF PAPER 

BY 

R. W. SINDALL, F.C.S. 

CONSULTING CHEMIST TO THE WOOD PULP AND PAPER TRADES ; LECTURER 

ON PAPER-MAKING FOR THE HERTFORDSHIRE COUNTY COUNCIL, THE 

BUCKS COUNTY COUNCIL, THE PRINTING AND STATIONERY 

TRADES AT EXETER HALL, 1903-4, THE INSTITUTE 

OF PRINTERS ; TECHNICAL ADVISER TO THE 

GOVERNMENT OF INDIA, 1905 

AUTHOR OF "paper TECHNOLOGY," " THE SAMPLING OF WOOD PULP " 

JOINT AUTHOR OF " THE C.B.S. UNITS, OR STANDARDS OF PAPER 

TESTING," " THE APPLICATIONS OF WOOD PULP," ETC. 



WITH ILLUSTRATIONS, AND A BIBLIOGRAPHY OF WORKS 
RELATING TO CELLULOSE AND PAPER-MAKING 




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11^ OCT 3 11910 
^^f-40 ^\^c> 



BU\ 



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A 



NEW YORK 

D. VAN NOSTRAND COMPANY 

23 MURRAY AND 27 WARREN STREETS 

1908 






By trassf»r trom 

U. S. Tariff Boarri 

1012 



/(o'?'<Q / 



PREFACE 

•Papee-making, in common with many other industries, is 
one in which both engineering and chemistry play important 
parts. Unfortunately the functions of the engineer and 
chemist are generally regai^dedi •a&n.inelepejident of one 
another, so that the chemist ife^o^ify e^llfeS-iii-hy the engineer 
when efforts along the lines of nlecTianical improvement 
have failed, and vice versa. It is impossible, however, to 
draw a hard and fast line, and the best results in the art of 
paper-making are only possible when the manufacturer 
appreciates the fact that the skill of both is essential to 
progress and commercial success. 

In the present elementary text-book it is only proposed 
to give an outline of the various stages of manufacture and 
to indicate some of the improvements made during recent 
years. 

The author begs to acknowledge his indebtedness to 
manufacturers and others who have given permission for the 
use of illustrations. 



CONTENTS 



PEEFACE 

LIST OF ILLUSTEATIONS 



CHAPTER 

I. HISTOEICAL NOTICE 



II. CELLULOSE AND PAPEE-MAKINa FIBEES . 

III. THE MANUFACTUEE OF PAPEE FEOM EAGS 

IV. ESPAETO AND STEAW .... 

^JS. WOOD PULP, AND WOOD PULP PAPEES 

VI. BEOWN PAPEES AND BOAEDS . 

VII. SPECIAL KINDS OF PAPEE 

VIII. CHEMICALS USED IN PAPEE-MAKING 

^IX. THE PEOCESS OF " BEATING" ... 

_ X. THE DYEING AND COLOUEING OF PAPEE PULP 

^XI. PAPEE MILL MACHINEEY 

XII. THE DETEEIOEATION OF PAPEE 

XIII. BIBLIOGEAPHY 

INDEX 



FAQE 

V 



1 

20 

47 

72 

95 

126 

137 

153 

175 

199 

214 

229 

253 

273 



LIST OF ILLUSTRATIONS 



^ SHEET OP PAPYRUS, SHOWING THE LAYERS CROSSING ONE 
ANOTHER . . 

2. AN EARLY PAPER MILL (fROM " KULTURHISTOEISCHEN BILDER 

BUCH,'.' A.D. 1564) 

3. THE PAPER MILL OP ULMAN STROMER, A.D. 1390 (SUPPOSED 

TO BE THE OLDEST KNOWN DRAWING OF A PAPER MILL) 

4. THE PIRST PAPER MACHINE, A.D. 1802. PLAN AND ELEVATION 

5. THE IMPROVED PAPER MACHINE OF A.D. 1810 

6. A RAG SORTING HOUSE 

7. A RAG DUSTER 

8. A RAG CUTTER 

9. INTERIOR OP PAPER MILL FOR HAND-MADE PAPER (r. BATCHELOR 

& sons) 

10. VIEW OF A RAG BOILER, SHOWING CONNECTIONS 

11. A BREAKING AND WASHING ENGINE 

12. OETTEL AND HAAS' APPARATUS FOR THE MANUFACTURE OF 

ELECTROLYTIC BLEACH LIQUOR .... 

13. THE " HOLLANDER " BEATING ENGINE . 

14. THE HAND MOULD, SHOWING FRAME AND DECKLE . 

15. APPARATUS FOR SIZING PAPER IN CONTINUOUS ROLLS 

16. A SUPERCALENDER 

17. THE FIRST WATERMARK IN PAPER 

18. COTTON ..... 

19. LINEN 

20. AN ESPARTO DUSTER 

21. SINCLAIR'S "vomiting" ESPARTO BOILER 

22. A PORION EVAPORATOR .... 

23. SCOTT'S MULTIPLE EFFECT EVAPORATOR 

24. A PEESSE-PATE FOR ESPARTO PULP 

25. ESPARTO PULP 

26. A CYLINDRICAL DIGESTER FOR BOILING FIBRE 

27. STRAW 

P. h 



10 

12 
17 
18 
47 
49 
50 

51 

52 
54 

58 
59 
61 
63 
65 
67 
69 
70 
74 
75 
76 
79 
85 
88 
89 
93 



X LIST OF ILLUSTRATIONS 

FIG. ' PAGE 

28. A PAIR OF BARKERS FOR REMOVING BARK FROM LOGS OF WOOD 98 

29. VIEW OF HORIZONTAL GRINDER (a), WITH SECTION (b) . . 99 

30. A VERTICAL GRINDER FOR MAKING HOT GROUND MECHANICAL 

WOOD PULP 101 

31. CENTRIFUGAL SCREEN FOR WOOD PULP 102 

32. SECTION OF CENTRIFUGAL SCREEN FOR WOOD PULP . . 103 

33. WOOD PULP DIGESTER, PARTLY IN ELEVATION, PARTLY IN 

SECTION 106 

34. VIEW OF ORDINARY SULPHUR-BURNING OVENS . . . 108 

35. SPRUCE WOOD PULP 114 

36. MECHANICAL WOOD PULP 115 

37. THE SCREENS FOR REMOVING COARSE FIBRES FROM BEATEN 

PULP 118 

SB. THE PAPER MACHINE (WET END SHOWING WIRB) . . . 119 

39. PAPER MACHINE SHOWING WIRB, PRESS ROLLS, AND DRYING 

CYLINDERS 123 

40. SINGLE CYLINDER OR YANKEE MACHINE .... 130 

41. SECTION OF WET PRESS, OR BOARD MACHINE . . . 131 

42. DOUBLE CYLINDER BOARD MACHINE 133 

43. APPARATUS FOR MAKING PARCHMENT PAPER .... 138 

44. GENERAL ARRANGEMENT OF PLANT FOR MAKING " ART " PAPER 143 

45. SECTIONAL ELEVATION OF " COATING " PLANT . . . 144 

46. COTTON PULP BEATEN 8 HOURS 179 

47. COTTON PULP BEATEN 37 HOURS 180 

48. PLAN AND SECTIONAL ELEVATION OF A "HOLLANDER". . 185 

49. BEATING ENGINE WITH FOUR BEATER ROLLS. . . . 186 

50. UMPHERSTON BEATER 188 

51. . SECTION OF UMPHERSTON BEATING ENGINE .... 189 

52. NUGENt's beating engine WITH PADDLES FOR CIRCULATING 

THE PULP 190 

53. A " tower" BEATING ENGINE WITH CENTRIFUGAL PUMP FOR 

CIRCULATING PULP . . . . . . . . 191 

54. WORKING PARTS OF A MODERN REFINING ENGINE . . . 192 

55. CONVENTIONAL DIAGRAM OF A WATER SOFTENING PLANT . 216 

56. AN " ENCLOSED " STEAM ENGINE . . . . ' . . 220 

57. AN ELECTRICALLY DRIVEN PAPER MACHINE .... 222 

58. DIAGRAM OF THE " EIBEL " PROCESS ..... 223 



THE MANUFACTURE 
OF PAPER 



CHAPTER I 

HISTOEICAL NOTICE 



History. — The art of paper-making is undoubtedly one of 
the most important industries of the present day. The 
study of its development from the early bygone ages when 
men were compelled to find some means for recording 
important events and transactions is both interesting and 
instructive, so that a short summary of the known facts 
relating to the history of paper may well serve as an intro- 
duction to an account of the manufacture and use of this 
indispensable article. 

Tradition. — The early races of mankind contented them- 
selves with keeping alive the memory of great achievements 
by means of tradition. Valiant deeds were further com- 
memorated by the planting of trees, the setting up of heaps 
of stones, and the erection of clumsy monuments. 

Stone Obelisks. — The possibility of obtaining greater 
accuracy by carving the rude hieroglyphics of men and 
animals, birds and plants, soon suggested itself as an 
obvious improvement ; and as early as b.c. 4000 the first 

p. B 



2 THE MANUFACTUEE OE PAPEE 

records which conveyed any meaning to later ages were 
faithfully inscribed, and for the most part consigned to the 
care of the priests. 

Clay Tablets. — The ordinary transactions of daily life, 
the writings of literary and scientific men, and all that was 
worthy of note in the history of such nations as Chaldea 
and Assyria have come down to us also, inscribed on clay 
tablets, which were rendered durable by careful baking. 
On a tablet of clay, one of the earliest specimens of writing 
in existence, now preserved in the British Museum, is 
recorded a proposal of marriage, written about b.c. 1530, 
from one of the Pharaohs, asking for the hand of the 
daughter of a Babylonian king. 

Waxed Boards. — Bone, ivory, plates of metal, lead, gold, 
and brass, were freely used, and at an early period wooden 
boards covered with wax were devised by the Eomans. In 
fact, any material having a soft impressionable surface was 
speedily adopted as a medium for the permanent expression 
of men's fancy, so that it is not strange to find instances of 
documents written on such curious substances as animal 
skins, hides, dried intestines, and leather. The works of 
Homer, preserved in one of the Egyptian libraries in the 
days of Ptolemseus Philadelphus, were said to have been 
written in letters of gold on the skins of serpents. 

Leaves, Bark. — The first actual advance in the direction of 
paper, as commonly understood, was made when the leaves 
and bark of trees were utilised. The latter especially came 
speedily into favour, and the extensive use of the inner bark 
{liber) made rapid headway. Manuscripts and documents 
written on this liber are to be found in many museums. 

Papyrus. — The discovery of the wonderful properties of 
the Egyptian papyrus was a great step in developing the 
art of paper-making. The date of this discovery is very 
uncertain, but one of the earliest references is to be found 



HISTOEICAL NOTICE 3 

in the works of Pliny, where mention is made of the writings 
of Numa, who Jived about B.C. 670. This celebrated plant 
had long been noted for its value in the manufacture of 



SIM ■. «».^-.S-^.-;. 


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1 „ ..: ^ii 
If ." 


■ ■■■' 'Hi;!.! . . 


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Fig. 1. — Sheet of Papyrus, showing the layers crossing one another 

(Evans). 

mats, cordage, and wearing apparel, but its fame rests upon 
its utility in quite a different direction, namely, for convey- 
ing to posterity the written records of those early days 
which have proved a source of unending interest to 
antiquaries. 

B 2 



4 THE MANUFACTUEE OF PAPER 

The Egyptian papyrus was made from the tine layers of 
tibrous matter surrounding the parent stem. These layers 
were removed by means of a sharp tool, spread out on a 
board, moistened with some gummy water, and then 
covered with similar layers placed over them crosswise. 
The sheets so produced were pressed, dried, and polished 
with a piece of ivory or a smooth stone. Long rolls of 
papyrus were formed by pasting several sheets together to 
give what was termed a volumen. 

Roman Pa'pyri. — The Eomans improved the process of 
manufacture, and were able to produce a variety of papers, 
to which they gave different names, such as Charta hieratica 
(holy paper, used by priests), Charta Fanniana (a superior 
paper made by Fannius), Charta emporetica (shop or wrap- 
ping paper), Charta Saitica (after the city of Sais), etc. The 
papyrus must have been used in great quantities for this 
purpose, since recent explorations in Eastern countries have 
brought to light enormous finds of papyri in a wonderful 
state of preservation. In 1753, when the ruins of Hercu- 
laneum were unearthed, no less than 1,800 rolls were 
discovered. During the last ten years huge quantities have 
been brought to England. 

Parchment. — Parchment succeeded papyrus as an excel- 
lent writing material, being devised as a substitute for the 
latter by the inhabitants of Pergamus on account of the 
prohibited exportation of Egyptian papyrus. For many 
centuries parchment held a foremost place amongst the 
available materials serving the purpose of paper, and 
even to-day it is used for important legal documents. This 
parchment was made from the skins of sheep and goats, 
which were first steeped in lime pits, and then scraped. 
By the plentiful use of chalk and pumice stone the colour 
and surface of the parchment v/ere greatly enhanced. 
Vellum, prepared in a similar manner from the skins of 



HISTOEICAL NOTICE 5 

calves, was also extensively employed as a writing material, 
and was probably the first material used for binding books. 
Until comparatively recent times the term " parchment " 
comprehended vellum, but the latter substance is much 
superior to that manufactured from sheep and goat skins. 

Paper. — The Chinese are now generally credited with the 
art of making paper of the kind most famiUar to us, that is 
from fibrous material first reduced to the condition of pulp. 
IVfaterials such as strips of bark, leaves, and papyrus cannot 
of course be included in a definition like this, which one 
writer has condensed into the phrase " Paper is an aqueous 
deposit of vegetable fibre." 

A.D. 105. — The earliest reference to the manufacture of 
paper is to be found in the Chinese Encyclopaedia, wherein 
it is stated that Ts'ai-Lun, a native of Kuei-yang, entered 
the service of the Emperor Ho-Ti in a.d. 75, and devoting 
his leisure hours to study, suggested the use of silk and ink 
as a substitute for the bamboo tablet and stylus. Sub- 
sequently he succeeded in making paper from bark, tow, 
old linen, and fish nets (a.d. 105). He was created marquis 
in A.D. 114 for his long years of service and his ability. 

A.D. 704. — It has been commonly asserted that raw 
cotton, or cotton wool, was first used by the Arabs at 
this date for the manufacture of paper, they having learnt 
the art from certain Chinese prisoners captured at the 
occupation of Samarkand by the Arabs. The complete 
conquest of Samarkand does not, however, seem to have 
taken place until a.d. 751, and there is little doubt that 
this date should be accepted for the introduction of the art 
of paper-making among the Arabs. 

Recent Researches. — Professors Wiesner and Karabacek 
have ascertained one or two most imjportant and inter- 
esting facts concerning the actual manufacture of pure 
rag paper. In 1877 a great quantity of ancient manuscripts 



6 THE MANUFACTUEE OF PAPER 

was found at El-Faijum, in Egypt, comprising about 
100,000 documents in ten languages, extending from b.c. 
1400 to A.D. 1300, many of which were written on paper. 
The documents were closely examined in 1894 by these 
experts, at the request of the owner, the Archduke Eainer 
of Austria. 

Eesearches of a later date resulted in the discovery 
of some further interesting documents which appear to 
estabUsh with some degree of certainty the approximate 
date at which jmre rag paper, that is, paper made entirely 
from rag, was manufactured. 

Chinese documents dated a.d. 768 — 786, which have been 
reported upon by Dr. Hoernle, and others dated a.d. 781 — 
782 — 787, reported upon by Dr. Stein as recently as 1901, 
appear to show what materials were used by the Chinese 
paper-makers in Western Turkestan. The manuscripts 
mentioned were dug out from the sand-buried site of 
Dandan Uilig, in Eastern Turkestan. 

Professor Wiesner found that all the papers of tiie Eainer 
collection were made of linen rag, with an occasional trace 
of cotton, probably added accidentally. The earliest dated 
paper was a letter a.d. 874, but two documents, which from 
other reasons could be identified as belonging to a.d. 792, 
proved that at the end of the eighth century the Arabs 
understood the art of making linen paper on network 
moulds, and further that they added starch for the purpose 
of sizing and loading the paper. 

Professor Karabacek advances some ingenious explana- 
tions as to the origin of the idea that raw cotton was first 
used for paper-making, and he suggests that the legend owes 
its origin to a misunderstanding of terms. In mediaeval 
times paper was known as Charta hombycina, and sometimes 
as Charta Damascena, the latter from its place of origin. 

Paper was also made in Bambyce, and a natural confusion 



HISTOEICAL NOTICE 7 

arose between the terms, since the word homhyx was used as 
a name for cotton, and the paper commonly in use suggested 
that material to the mind of the observer, and the name 
became corrupted to homhycina. 

The suggestions of Professor Karabacek, together with 
the microscopical investigations of Dr. Wiesner, appear to 
show that paper made entirely from raw cotton fibre was 
not known. 

Invention of Rag Paper. — Dr. Hoernle, in discussing this • 
question, points out that, taking a.d. 751 as the date when 
the Arabs learnt the art of paper-making, and a.d. 792 as 
the date when paper made entirely of linen rag was pro- 
duced, the date of the invention of rag paper must lie 
between these two dates. The documents discovered in 
Eastern Turkestan and bearing the dates mentioned, which 
papers fill up the gap between the years a.d, 751 and 
A.D. 792, were found to contain certain raw fibres, such as 
China grass, mulberry, laurel, as the main constituents, 
and macerated flax and hemp rags as the minor con- 
stituents. 

The addition and substitution of rag evidently increased 
in course of time, and since the improvement thus effected 
soon became an obvious and established fact, the raw fibres 
were omitted. Hence the credit of the manufacture of pure 
rag paper would be given to the people of Samarkand, tbe 
date being between the years a.d. 760 and a.d. 792 ; and 
further the constitution of such paper has been shown by 
Dr. Wiesner to be linen, and not cotton, as commonly 
stated. 

These researches are of such interest that we quote 

Professor Hoernle's translation of the summary of the 

principal results of Dr. Wiesner 's examination of the 

Eastern Turkestani papers so recently discovered :— 

" Taking into account the dates assigned to the papers on 



8 THE MANUFACTUEE OF PAPEE 

palseographic grounds, the following conclusions may be 
drawn from the examination of their material : — 

"(1) The oldest of the Eastern Turkestani papers, dating 
from the fourth and fifth centuries a.d., are made of a 
mixture of raw fibres of the bast of various dicotyledonous 
plants. From these fibres the half-stuff for the paper was 
made by means of a rude mechanical process. 

"(2) Similar papers, made of a mixture of raw fibres, 
are also found belonging to the fifth, sixth, and seventh 
centuries. But in this period there also occur papers 
which are made of a mixture of rudely pounded rags and 
of raw fibres extracted by maceration. 

" (3) Jn the same period papers make their appearance 
in which special methods are used to render them cajoable 
of being written on, viz., coating with gypsum and sizing 
with starch or with a gelatine extracted from lichen. 

" (4) In the seventh and eighth centuries both kinds of 
papers are of equal frequency, those made of the raw fibre 
of various dicotyledonous plants and those made of a mixture 
of rags and raw fibres. In this period the method of extract- 
ing the raw fibre is found to improve from a rude stamping 
to maceration ; but that of preparing the rags remains a 
rude stamping, and in the half-stuff thus produced from 
rags it is easy to distinguish the raw fibre from the crushed 
and broken fibre of the rags. 

" (5) The old Eastern Turkestani (Chinese) paper can be 
distinguished from the old Arab paper, not only by the raw 
fibres which accompany the rag fibres, but also by the far- 
reaching destruction of the latter. 

" (6) The previous researches of Professor Karabacek and 
the author had shown that the invention of rag paper was 
not made in Europe by Germans or Italians about the turn 
of the fourteenth century, but that the Arabs knew its 
preparation as early as the end of the eighth century. 



HISTOEICAL NOTICE 

" The present researches now further show that the 
beginnings of the preparation of rag paper can be traced 
to the Chinese in the fifth or fourth centuries, or even 
earlier. 

" The Chinese method of preparing rag paper never pro- 
gressed beyond its initial low stage. It was the Arabs who, 
having been initiated into the art by the Chinese, improved 
the method of preparing it, and carried it to that stage of 
perfection in which it was received from them by the 
civilised peoples of Europe in the mediseval ages. 

" (7) The author has shown that the process of sizing the 
paper with starch in order to improve it was already known 
to the Arabs in the eighth century. In the fourteenth 
century the knowledge of it was lost, animal glue being 
substituted in the place of starch, till finally in the nine- 
teenth century, along with the introduction of paper 
machines, the old process was resuscitated. But the inven- 
tion of it was due to the Chinese. The oldest Eastern 
Turkestani paper which is sized with starch belongs to the 
eighth century. 

" (8) The Chinese were not only the inventors of felted 
paper and the imitators of rag paper — though in the pre- 
paration of the latter they made use of rags only as a 
surrogate by the side of raw fibres — but they must also be 
credited with being the forerunners of the modern method 
of preparing ' cellulose paper.' For their very ancient 
practice of extracting the fibre from the bark and other 
parts of plants by means of maceration is in principle 
identical with the modern method of extracting ' cellulose ' 
by means of certain chemical processes." 

Paper-making in Euroije. — The introduction of the art 
into Europe seems to have taken place early in the eleventh 
century, when the Moors manufactured paper at Toledo. 
The early authorities who have studied this subject express 



10 



THE MANUFACTUEE OF PAPEE 




Fig. 2. — An Early Paper Mill (from " Kulturhistorischen Bilderbuch," 

A.D. lo6i). 



HISTOEIOAL NOTICE 11 

the opinion that the paper produced in Europe at this 
time was made from cotton rags and from raw cotton, 
but, in view of the recent researches into the composition of 
paper, it is difficult to say how this idea arose, unless we 
accept the explanation offered by Professor Karabacek. In 
standard encyclopaedias the following statements are made 
as to existing early documents printed on paper made in 
Europe: — 

A.D. 1075. Syriac manuscripts of early date in the British 

Museum. 
A.D. 1102. A document printed on cotton, being a deed 

of King Eoger of Sicily, now at Vienna. 
A.D. 1178. A treaty of peace between the Kings of 

Aragon and Spain, said to be printed on 

linen paper, preserved at Barcelona. 
A.D. 1223. The "Liber Plegierum," printed on rough 

cotton paper. 

One of the most interesting books on this subject is the 
" Historical Account of the Substances used to describe 
Events from the Earliest Date," by Matthias Koops, pub- 
lished in 1800. This writer appears to have obtained most 
of his information from German authorities. 

The industry of paper-making passed through Spain 
into Italy, France, and the Netherlands. In 1189 paper 
was being manufactured at Hainault, in France, and the 
industry rapidly spread all over the Continent. In 1390 
Ulman Stromer established a mill at Nuremberg, in Ger- 
many, employing a great number of men, who were obliged 
to take an oath that they would not teach anyone the art 
of paper-making or make paper on their own account. In 
the sixteenth century the Dutch endeavoured to protect 
their industry by making the exportation of moulds for 
paper-making an offence punishable by death. 



12 



THE MANUFACTUEE OF PAPER 



The bulk of the paper used in England was imported 
from France and Holland, and it was many years before 
the industry was established in England. This is not sur- 



O " <-J 




Fig. 3.— The Paper Mill of Ulman Stromer, a.d. 1390 (supposed to be 
the oldest known drawing of a Paper Mill}. 



prising in view of the protective and conservative policy of 
the Continental paper-makers. 

Paper-making in England. — The actual period at which 
the manufacture of paper was first started in England is 
somewhat uncertain. The first mention of any paper-maker 
is found in Wynkyn de Worde's " De Proprietatibus 



HISTORICAL NOTICE 13 

Kerum," printed by Caxton in 1495, the reference being as 
follows : — 

And John Tate the younger, joye mote lie brok, 
Whicli late hatlie in England, doo 
Make thys paper thynne, 
That now in our Englyssh 
Thys booke is prynted inne. 

John Tate was the owner of a mill at Stevenage, Hertford- 
shire. In the household book of Henry VII. an entry for 
the year 1499 reads, " Geven in rewarde to Tate of the 
mylne, 6s. 8d." 

In 1588 a paper mill was erected by Sir John Spielman, 
a German, who obtained a licence from Queen Elizabeth 
" for the sole gathering for ten years of all rags, etc., 
necessary for the making of paper." This paper mill was 
eulogised by Thomas Churchyard in a long poem of forty- 
four stanzas, of which we quote two : — 

I prayse the man that first did paper make, 
The only thing that sets all virtues forth ; 

It shoes new bookes, and keeps old workes awake. 
Much more of price than all the world is worth : 

It witnesse bears of friendship, time, and troth. 

And is the tromp of vice and virtue both ; 

Without whose help no hap nor wealth is won. 

And by whose ayde great works and deedes are done. 

Six hundred men are set to worke by him 

That else might starve, or seeke abroad their bread, 

Who now live well, and goe full brave and trim, 
And who may boast they are with paper fed. 

Strange is that foode, yet stranger made the same, 

Eor greater help, I gesse, he cannot give 

Than by his help to make poore folk to live. 

The industry made but little progress for some time after 
Spielman's death, and up till 1670 the supplies of paper 
were obtained almost entirely from France. The first 
British patent for paper-making was granted to Charles 



14 THE MANUFACTUEE OF PAPEE 

Hildeyard in 1665 for " the way and art of making blue 
paper used by sugar bakers and others." The trade 
received a great impetus on account of the presence of 
Huguenots who had fled to England from France in con- 
sequence of the revocation of the edict of Nantes in 1685. 
In 1695 a company was formed in Scotland for the 
"manufacture of white and printing paper." 

Improvements in the art were slow until 1760, when 
Whatman, whose name has since become famous in connec- 
tion with paper, commenced operations at Maidstone. 
Meantime the methods by which the rags were converted 
into paper were exceedingly slow and clumsy, so that the 
output of finished paper was very small. 

Some interesting details as to the early manufacture of 
paper in England are given by Mr. Ehys Jenkins, and from 
his account of "Early Attempts at Paper-making in 
England, 1495 — 1788," the following extracts have been 
made : — 
About 

1496. First attempts at paper-making by Jobn Tate at Hertford. 
1496. Tate's paper used by Wynkyn de Worde in " De Proprietatibus 

Eerurn." 
1557. A paper mill in existence at Fenditton, Cambridge. 
1569. A mill at Bemmarton, Wilts. 

1574. Mill erected at Osterley, Middlesex, by Sir Thomas Gresbam. 
1585. Eicbard Tottyl asked for sole rigbt to make paper for tbirty- 

one years, wbicb was not granted. 
1588. Jobn Spilman erected a mill at Dartford, Kent. Granted a 

patent for sole manufacture of paper. 
1588. Churchyard's poem on the "Paper Myll built near Darthford by 

Master Spilman." 
1612. Eobert Heyricke's mill at Cannock Chase, Stafi'oi'dshire. 
1636. The three or four paper mills in the neighbourhood of Hounslow 

and Colnbrook temporarily shut down on account of the plague, 

the collection of i-ags having been forbidden. 
1665. Patent granted to Charles Hildeyard for an invention, " the way 

and art of making blew paper used by sugar bakers and 

others." 



HISTOEICAL NOTICE 15 

About 

1675. Approximate date of erection of mills at Wolvercote, Oxford, 

where the Oxford India paper is now made. 
1678. Mill at Byfieet, Surrej', mentioned by Evelyn in bis diary. 
1682. Bladen — A patent for an engine and process whereby rags are 

wrought into paper. 
1684. Baysmaker — A patent for "the art and mistery of making paper 

in whole sheets." 
1684. Jackson — A patent for "an engine, either for wind or water, which 

prepareth all materials whereof paper may be made." Evi- 
• dently Jackson was acquainted with the "Hollander " beating 

engine. 
1686. A charter granted to the "White Paper Makers' Company " for 

the sole right of making paper exceeding 4s. a ream in value. 
1674. Annual importation of paper, presumably from France, stated to 

be 160,000 reams, of average value of os. (Somers). 
1689. Trade with France prohibited by royal proclamation. 
1696. Price of paper very high owing to scarcity, being lis. per 

ream. 
1712. Duties levied on all kinds of paper, manufactured or imported. 
1725. Monopoly of making paper for Bank of England notes granted 

to De Portal, of the Laverstoke mills, Hampshire. This paper 

is still made by the firm of Messrs. Portal. 
1739. Galliott and Parry estimated that there were 600 paper mills in 

England, making 6,000 reams a day. The Commissioner of 

Excise reported only 278. 
1739. James Whatman erected a mill at Boxley, Maidstone. 
1758. Baskerville printed an edition of Virgil on so-called " woven " 

paper. 

Early Methods. — The most rapid development of the 
industry appears to have taken place in Holland. The rags 
used for paper-making were moistened with water and 
stored up in heaps until they fermented and became hot. 
By this means the dirt and non-fibrous matter was rendered 
partially soluble, so that on washing a suitable paper pulp 
wa§ obtained. The washed rags were then placed in a 
stamping machine resembling an ordinary pestle and 
mortar. The mortars were constructed of stone and wood, 
and the stamps were kept in motion by levers which were 



16 THE MANUFACTURE OF PAPER 

raised by projections fixed on the shaft of a water wheel. 
The operation of beating thus occupied a long period, but 
the paper produced was of great strength. 

The invention of the "Hollander," a shnple yet inge- 
nious engine which is deservedly known by the name of the 
country in which it first originated, gave a tremendous 
impetus to the art of paper-making, as by its means the 
quantity of material which could be treated in twenty -four 
hours was greatly increased. Unfortunately the date of 
the invention of this important machine has not been 
definitely traced. The earliest mention of it seems to occur 
in Sturm's " Vollstandige Muhlen Baukunst," published in 
1718. It was in extensive use at Saardam in 1697, so that 
the invention is at least some years previous to 1690. 

On this point Koops says: "In Gelderland are a great 
many mills, but some so small that they are only able 
to make 400 reams of paper annually, and there are 
also water mills with stampers, like those in Germany. 
But in the province of Holland there are windmills, with 
cutting and grinding engines, which do more in two hours 
than the others do in twelve. In Saardam 1,000 persons 
are employed in paper-making." 

The First Fourdeinier Paper Machine. 

Up till the year 1799 paper was made entirely in sheets 
on a hand mould, but during the last few years of the 
eighteenth century a Frenchman, Nicholas Louis Eobert, 
manager for M. Didot, who owned a paper mill at 
Essones, had been experimenting for the purpose of making 
paper in the form of a continuous sheet, and eventually 
produced some of considerable length. 

The idea was taken to England by Didot's brother-in-law, 
Gamble, and introduced to the notice of Messrs. Fourdrinier, 
wholesale stationers, of London. 



HISTOEIOAL NOTICE 



17 



The first machine was naturally a very crude affair. It 
consisted of an endless wire cloth stretched in a horizontal 




Fig. 4. — The First Paper Machine, a.b. 1802. Plan and Elevation. 

position on two rollers, one of which rotated freely in a 
bearing attached to the frame of the machine, the other 
being fitted in an adjustable bearing so that the wire could 
be tightened up when necessary. 

p. c 



18 



THE MANUFACTUEE OF PAPER 



The beaten pulp, contained in a vat placed below the 
wire, was thrown up in a continual stream upon the surface 
of the wire, and carried forward towards the squeezing rolls. 
A shaking motion was imparted to the travelling wire so as 
to cause the fibres to felt properly. A great deal of the 
water fell through the meshes of the gauze, and further 
quantities were removed by means of the press rolls. The 
wet paper was then wound up on to a wooden roller, which 
was taken out as soon as sufficient paper had been made. 

The whole process was carried on under great difficulties, 
but substantial improvements were soon made by the 




Fig. 5. — The Improved Paper Machine of a.d. 1810. 

enterprising Fourdriniers, who commenced operations in 
Bermondsey, employing Mr. Bryan Donkin, then in the 
service of Messrs. Hall & Co., of Dartford, who had 
shown himself keenly interested in the machine. In 1803 
the first " Fourdrinier," so called, was built at Bermondsey, 
and erected at Two Waters Mill in Herefordshire. 

In this machine the mixture of pulp and water was 
carried forward between two wires, and, after passing through 
the couch rolls, transferred to an endless felt. This 
arrangement proved to be faulty because the water did not 
escape freely enough from the wire, and a great deal of the 
paper was spoilt. 



HISTOEIOAL NOTICE 19 

Donldn, however, hit upon a simple but effective device 
for curing this fault by altering the relative position of the 
two couch rolls. Instead of keeping the two rolls exactly in 
a vertical position one over the other, he placed them at a 
slight angle so that the upper one should bear gently on 
the web of paper carried by the wire before receiving the 
full pressure of the rolls, and thus remove a greater pro- 
portion of the water. In this way the paper was firmer 
and less liable to break when pressed between the couch 
rolls, an additional advantage being secured in the fact that 
the upper wire could be dispensed with. 

The various improvements effected resulted in a machine 
the details of which appear in the appended diagram, the 
device of the inclined couch rolls being fitted about 1810. 

The mixture of water and pulp flowed from a stuff chest 
into a small regulating box and on to the wire over a 
sloping board. The pulp at once formed into a wet sheet 
of paper, the water falling through the meshes of the wire, 
being caught in a bucket-shaped appliance, and conveyed 
back to the regulating box. The stream of pulp was 
confined upon the wire by means of a deckle. Further 
quantities of water were removed by the aid of a pair of 
squeezing rolls before the web passed through the couch- 
rolls, after which the paper was reeled up on a wooden 
spindle. 

From this date the success of the machine was assured, 
though the inventor and his colleagues were practically 
ruined, an experience only too common with the early 
pioneers of many great and useful industrial enterprises. 
In fact, the firm of Messrs. Donkin were the only people to 
profit from the invention, for they manufactured a number 
of machines, as stated in the report of the Jurors of the 
Exhibition of 1851, and from 1803 to 1851 no less than 190 
Fourdriniers were set to work. 

c 2 



CHAPTEE II 

CELLULOSE AND PAPER-MAKING FIBRES 

When plants such as flax, cotton, straw, hemp, and other 
varieties of the vegetable kingdom are digested with a 
solution of caustic soda, washed, and then bleached by 
means of chloride of lime, a fibrous mass is obtained more 
or less white in colour. 

This is the substance known to paper-makers as paper 
pulp, and the several modifications of it derived from 
different iDlants are generally known to chemists as 
cellulose. 

Although plants differ greatly in physical structure and 
general appearance, yet they all contain tissue which under 
suitable treatment yields a definite proportion of this fibrous 
substance. The preparation of a small quantity of cellulose 
from materials like straw, rope, hemp, the stringy bark of 
garden shrubs, wood, and bamboo can easily be accomplished 
without special appliances. Soft materials, such as straw 
and hemp, are cut up into short pieces, hard substances like 
wood and bamboo are thoroughly hammered out, in order 
to secure a fine subdivision of the mass. The fibre so pre- 
pared is then placed in a small iron saucepan, and covered 
with a solution made up of ten parts of caustic soda and 
100 parts of water. The material is boiled gently for eight 
or ten hours, the water which is lost through evaporation 
of steam being replaced by fresh quantities of hot water at 
regular intervals. When the fibrous mass breaks up readily 
between the fingers, it is poured into a sieve, or on a piece 



CELLULOSE AND PAPEE-MAKING FIBEES 21 

of muslin stretched over a basin, and washed completely 
with hot water until clean and free from alkali. Hard 
pieces and portions which seem incompletely boiled are 
removed, and the residual fibres separated out. These 
fibres are placed in a weak, clear solution of ordinary 
bleaching powder, left for several hours, and subsequently 
thoroughly washed. This simple process will give a more or 
less white fibroug material. 

The purest form of cellulose is cotton. A very slight 
alkaline treatment, followed by bleaching, is sufficient to 
remove the non-fibrous constituents of the plant, and a 
large yield of cellulose is obtained. For this reason the 
cotton fibre ranks high as an almost ideal material for 
paper-making, possessing the quality of durability. 

Cellulose is an organic compound, containing carbon, 
hydrogen, and oxygen in the following proportions : — 

Carbon .... 44*2 
Hydrogen .... 6*3 

Oxygen . . . . 49 '5 



100-0 



Its composition is represented by the formula Ce Hio O5. 

The celluloses obtained from various plants are not 
identical either in physical structure and chemical constitu- 
tion, or as to their behaviour when employed for paper- 
making. In fact, the well-known differences between the raw 
materials used for paper-making, and also between the 
numerous varieties of finished paper, are to be largely 
accounted for and explained by a careful study of the 
cellulose group, particularly w ith reference to the microscopic 
characteristics and the chemical composition of the individual 
species. 

The only vegetable substance which may be regarded as 



22 THE MANUFACTUEE OF PAPER 

a simple cellulose is cotton, all others being compound 
celluloses of varying constitution, the natm'e of which 
cannot be appreciated without a considerable knowledge of 
chemistry. The classification of such plants, therefore, in 
a book of this description must be limited to certain dis- 
tinctions having some immediate practical bearing on the 
question of paper manufacture. 

Cotton. — Eegarded as the typical simple cellulose, contain- 
ing 91 per cent, of cellulose, and remarkable for its resistance 
to the action of caustic soda. 

Linen. — The cellulose isolated from flax by treatment 
with alkali or caustic soda cannot readily be distinguished 
from cotton cellulose by chemical analysis or reactions. 
The difference is almost entirely a physical one. 

Flax is a typical compound cellulose, to which has been 
given the name pecto-cellulose on account of certain pro- 
perties. Other well-known plants of this class are ramie, 
aloe, " sunn hemp," manila. 

Esparto. — The cellulose isolated from esparto differs in 
composition from cotton cellulose : — 

Carbon .... 41-0 
Hydrogen .... 5"8 

Oxygen .... 53'2 



100-0 



It is regarded as an oxycellulose, being readily oxidised 
by exposure to air at 100° C. Other oxycelluloses familiar 
to the paper-maker are straw, sugarcane, bamboo. 

Wood. — The difference between wood and the plants 
already mentioned is expressed by the term lignified 
fibre or ligno-cellulose. This term is used to indicate that 
the wood is a compound cellulose containing non-fibrous 



CELLULOSE AND PAPER-MAKING FIBRES 23 

constituents, to which has been given the name lignone. 
Jute is another example of this class. 

These distinctions may be exemplified by reference to a 
simple experiment. If three papers, such as a pure rag 
tissue or a linen writing, an ordinary esparto printing, and a 
cheap newspaper containing about 80 per cent, of mechanical 
wood, are heated for twenty-four hours in an oven at a 
temperature of 105*^ C, the first will undergo little, if any, 
change in colour, while the others will be appreciably 
discoloured, the mechanical wood pulp paper most of all. 

This change is due to the gradual oxidation of the con- 
stituents of the paper, the ligno-cellulose of the mechanical 
wood pulp being most readily affected by the high tempera- 
ture, and the pure cellulose of the rag paper being least 
altered. 

The process of oxidation, brought about rapidly under the 
conditions of the experiment described, takes place in papers 
of low quality exposed to air in the ordinary circumstances 
of daily use, but of course at an extremely slow rate. The 
deterioration of such paper is not, however, due to the simple 
oxidation of the cellulose compounds, because other factors 
have to be taken into account. The presence of impurities 
in the paper on the one hand, and of chemical vapours in 
the air on the other, hastens the decay of papers very 
considerably. 

Percentage of Cellulose in Fibrous Plants. — The value of 
a vegetable plant for paper-making is first determined by a 
close examination of the physical structure of the cellulose 
isolated by the ordinary methods of treatment. If the 
fibres are weak and short, the raw material is of little 
value, and it is at once condemned without further inves- 
tigation, but should the fibre prove suitable, then the 
question of the percentage of cellulose becomes important. 



24 THE MANUFACTUEE OE PAPER 

There are several methods employed for estimating the 
amount of cellulose in plants. The process giving a 
■maximum yield is known as the chlorination method, the 
details of which are as follows : — About ten grammes of the 
air-dried fibre is dried at 100° C. in a water oven for the 
determination of moisture. A second ten grammes of the 
air- dried fibre is boiled for thirty minutes with a weak solution 
of pure caustic soda (ten grammes of caustic soda in 1,000 
cubic centimetres of water), small quantities of distilled 
water being added at frequent intervals to replace water 
lost by evaporation. The residue is then poured on to a 
piece of small wire gauze, washed thoroughly, and squeezed 
out. The moist mass of fibre is loosened and teased out, 
placed in a beaker, and submitted to the action of chlorine 
gas for an hour. The bright yellow mass is then washed 
with water and immersed in a solution of sodium sulphite 
(twenty grammes of sodium sulphite in 1,000 cc. of 
water). The mixture is slowly heated, and finally boiled 
for eight to ten minutes, with the addition of 10 cc. 
of caustic soda solution. The residue is washed, immersed 
in dilute sodium hypochlorite solution for ten minutes, 
again washed, first with water containing a little sulphurous 
acid and then with pure distilled water. It is finally dried 
and weighed. 

The second process for estimating cellulose is based upon 
the use of bromine and ammonia. About ten grammes of the 
air-dried fibre is placed in a well-stoppered wide-mouthed 
bottle with sufficient bromine water to cover it. As the 
reaction proceeds the red solution gradually decolourises, 
and further small additions of bromine are necessary. The 
mass is then washed, and boiled in a flask connected to a 
condenser with a strong solution of ammonia for about 
three to four hours. The fibrous residue is washed, again 
treated with bromine water in the cold, and subsequently 



CELLULOSE AND PAPEB-MAKING EIBEES 25 

boiled with ammonia. The alternative treatment with 
bromine and ammonia is repeated until a white fibrous 
mass is obtained. 

In practice the paper-maker is confined to two or three 
methods for the isolation of the fibres, viz., alkaline pro- 
cesses, which require the digestion of the material with 
caustic soda, lime, lime and carbonate of soda, chiefly 
applied to the boiling of rags, esparto, and similar pecto- 
c^uloses ; acid processes, in which the material is digested 
with sulphurous acid and sulphites. The latter methods 
are at present almost exclusively used for the preparation 
of chemical wood pulp. 

Yields of Cellulose in the Paper Mill. — The object of the 
paper-maker is to obtain a maximum yield of cellulose 
residue at a minimum of cost. Usually the amount of 
actual bleached paper pulp obtained in the mill is less than 
the percentage obtained by careful quantitative analysis, 
for reasons easily understood. 

In the first place, the raw material is digested for a stated 
period with a carefully measured quantity of caustic soda, 
for example, at a certain temperature. Now the conditions 
of boiling may be varied by altering one or more of these 
factors, the period of boiling, the strength of solution, or 
the steam pressure, and the paper-maker must exercise his 
judgment in fixing the exact relation between the varying 
factors so as to produce the best results. 

In the second place, the mechanical devices for washing 
the boiled pulp and for bleaching cause slight losses of 
fibre, which cannot be altogether avoided when operations 
are conducted on a large scale. Frequently, also, a greater 
yield of boiled material may involve a larger quantity of 
bleaching powder, so that it is evident the adjustment of 
practical conditions requires considerable technical skill and 
experience. 



26 



THE MANUEAOTUEE OF PAPER 



The percentage of cellulose in the vegetable plants 
employed more or less in the manufacture of paper is given 
in the following table : — 

Table showing Percentage of Cellulose in Fibrous Plants. 



Fibre. 


Cellulose, per cent. 


Cotton 


91-0 


Flax 


82-0 


Hemp 
Ramie 


77-0 
76-0 


Manila 


64-0 


Jute 


64-0 


Wood (pine) 

Bagasse 

Bamboo 


57-0 
50-0 
48-0 


Esparto 

Straw 


48 to 42 
48 to 40 



The Properties of Cellulose. — Cellulose is remarkably 
inert towards all ordinary solvents such as water, alcohol, 
turpentine, benzene, and similar reagents, a property which 
renders it extremely useful in many industries, with the 
result that the industrial applications of cellulose are 
numerous and exceedingly varied. 

Solubility. — Cellulose is dissolved when brought into con- 
tact with certain metallic salts, but it behaves quite diffe- 
rently to ordinary organic compounds. Sugar, for example, 
is a crystalline body soluble in water, and can be recovered 
in a crystalline state by gradual evaporation of the water. 
Cellulose under suitable conditions can be dissolved, but it 
cannot be reproduced in structural form identical with the 
original substance. 

If cellulose is gently heated in a strong aqueous solution 
of zinc chloride, it gradually dissolves, a thick syrupy mass 
being obtained, which consists of a gelatinous solution of 



CELLULOSE AND PAPEE-MAKING EIBEES 27 

cellulose. If the mixture is diluted with cold water, a pre- 
cipitate is produced consisting of cellulose hydrate intimately 
associated with oxide of zinc, which latter can be dissolved 
out by means of hydrochloric acid. The resulting product 
is not, however, the original substance, but a hydrated 
cellulose, devoid of any crystalline structure. 

Cellulose is also soluble in ammoniacal solutions of cupric 
oxide, from which it can be precipitated by acids or by 
substances which act as dehydrating agents, e.g., alcohol. 

Hydrolysis. — An explanation of the behaviour of cellulose 
towards the solvents already mentioned, and towards 
acid and alkali, requires a reference to its chemical 
composition. 

The substance is a compound of carbon, hydrogen, and 
oxygen represented by the formula 

Ce Hio O5 

being one of a class of organic compounds known as carbo- 
hydrates, so designated because the hydrogen and oxygen 
are present in the proportions which exist in water. 

Water == Hydrogen + Oxygen 
H2 + 0. 

The Hio O5 in the cellulose formula corresponds to 
5 (H2 0). 

When cellulose is acted upon by acid, alkali, and certain 
metallic salts, it enters into combination with one or more 
proportions of water, forming cellulose hydrates of varying 
complexity. This change is usually termed hydrolysis. 

With mineral acids like sulphuric and hydrochloric acids, 
cellulose, if boiled in weak solutions, is converted into a 
non-fibrous brittle substance having the composition 

C12 H20 Oio 2 H2 
to which the name hydra-cellulose has been given. Similar 
changes occur, but at a much slower rate, when cellulose is 



28 THE MANUFACTURE OF PAPER 

in contact with free acids at ordinary temperatures. For this 
reason it is important that paper, when finished, should not 
be contaminated with free acid. 

The nature and extent of the chemical change can be 
varied by altering the strength of the acid and the con- 
ditions of treatment. The manufacture of parchment paper 
is an example of the practical utility of the chemical reaction 
between cellulose and acid. A sheet of paper is dipped into 
a mixture of three parts of strong sulphuric acid and one 
part of water, when it becomes transparent. Left in the 
solution it dissolves, but if taken out and dipped into water 
in order to wash off the acid the reaction is stopped, and a 
tough semi-transparent piece of parchment is obtained. The 
cellulose is more or less hydrated, having the composition 

Cl2 H20 Oio H2 0, 
a substance having the name amyloid. 

Oxidation. — Cellulose is only oxidised to any appreciable 
extent by acid and alkali if treated under severe condi- 
tions. It is remarkable that the processes necessary for 
isolating paper pulp from plants when digested with these 
chemical reagents do not act upon or destroy the fibre, and 
this capacity for resisting oxidation has rendered cellu- 
lose extremely valuable to many of the most important 
industries. 

The resistant power of the cellulose is, however, 
broken down by the use of acid and alkali in concentrated 
form. 

Oxalic and acetic acids are obtained when cellulose is 
heated strongly at 250° C. with solid caustic soda. 

Oxy-cellulose, a white friable powder, is produced by means 
of strong mineral acids. Nitric acid at 100° C. attacks the 
fibre very readily and produces about 30 — 40 per cent, of 
the oxidised cellulose. 



CELLULOSE AND PAPER-MAKING FIBEES 29 



Cellulose Derivatives. 

The great number of compounds and derivatives, i.e., 
substances obtained by chemical treatment, may be judged 
from the following list. The substances of commercial 
importance are suitably distinguished from those of merely 
scientific interest by the printing of the names in small 
capitals. 

Acetic Acid. — An important commercial product obtained 
by the destructive distillation of wood. The crude 
pyroligneous acid is first neutralised with chalk or 
lime, and the calcium acetate formed then distilled 
with sulphuric acid. Wood yields 5 to 10 per cent. 
of its weight of acetic acid according to the nature 
of the wood. 

Acetone. — A solvent for resins, gums, camphor, gun cotton, 
and other cellulose jproducts. Prepared by distilling 
barium or calcium acetate in iron stills, the acetate 
being obtained from the crude acetic acid produced by 
the dry distillation of wood. 

Acid Cellulose. — (See Hydral-Cellulose.) 

Adipo-Cellulose. — A distinct compound cellulose present in 
the complex cuticular tissue of plants, and separated 
easily by suitable solvents from the wax and oily 
constituents also present. 

Alkali Cellulose. — When cotton pulp is intimately mixed 
with strong caustic soda solution, this compound is 
formed. It is utilised in the manufacture of Viscose. 

Amyloid. — Strong sulphuric acid acts upon cellulose and 
converts it into a gelatinous semi-transparent substance 
to which the name amyloid has been given. (See 
Parchment Paper.) 



30 THE MANUFACTUEE OF PAPEE 

Ballistite, — A smokeless powder composed of nearly equal 
parts of nitro-glycerine and nitrated cellulose, with a 
small quantity of diphenylamine. 

Carbohydrate. — A large number of important commercial 
products, such as cellulose, sugars, starches, and gums, 
consist of the elements carbon, hydrogen, and oxygen, 
associated in varying proportions. The ratio of 
hydrogen to oxygen in these compounds is always 2 : 1 
(Ha and 0). 

Cellulose Ce Hio O5. 
Sugar CeHiaOe- 

Dextrin n (Ce Hio O5). 

To all these substances the term carbohydrate is 
applied. 

Celloxin (Tollens). — A substance having the stated com- 
position CsHfiOe considered to be present in oxidised 
derivatives of cellulose. 

Celluloid. — This well-known material is made by incor- 
porating camphor with nitro-cellulose, a plastic ivory- 
like substance being produced. In practice the process 
is as follows : — Wood pulp or wood puljp paper is 
saturated with a mixture of sulphuric acid (five parts) 
and nitric acid (two parts), which produces nitrated 
cellulose. The product is washed, ground, and mixed 
with camphor, the mastication being effected by heavy 
iron rollers. The mass thickens and can be removed 
in the form of thick sheets. These sheets are submitted 
to great pressure between steam-heated plates. The 
cake obtained is cut into sheets of any desired thick- 
ness, seasoned by prolonged storage, and afterwards 
worked up into boxes, combs, brush-backs, and many 
other domestic articles of a useful and ornamental 
character. 



CELLULOSE AND PAPEE-MAKING EIBRES 31 

Cellulose Acetate (Cross). — If cellulose is heated with 
acetic anhydride at 180° C, viscous solutions of the 
acetates are obtained. The process yielding a definite 
acetate of commercial value is based upon the following 
reaction : — 100 parts of cellulose prepared from the 
sulpho-carbonate are mixed with 120 parts of zinc 
acetate, heated and dried at 105° C. Acetic anhydride 
is added in small quantity, and 100 parts of acetyl 
* chloride. At a temperature of 50° C. the mixture 
becomes liquid, and cellulose acetate is subsequently 
obtained as a white powder. 

The compound can be used in the place of cellulose 
nitrate, and, being non-explosive, may gradually replace 
the latter in many industrial applications. 
Cellulose-Benzoate. — When alkali cellulose is heated with 
benzoyl chloride and excess of caustic soda, this 
substance is obtained. 
Cellulose Hydrate. — The substances produced by the action 
of acid and alkali on cellulose under certain strictly 
defined conditions are bodies containing cellulose 
united with water to form hydrates. The industrial 
applications of cellulose based upon this reaction are 
described under the special headings. 
Cellulose Nitrate. — A considerable number of derivatives 
are obtained by bringing cellulose into contact with nitric 
acid. Variations in the strength of the acid, the tempera- 
ture of reaction, and the time of contact determine the 
nature of the product. The best known nitrates are : — 
Cellulose di-nitrate. 
Cellulose tri-nitrate and tetra-nitrate, present chiefly 

in pyroxyline. 
Cellulose penta-nitrate. 

Cellulose hexa-nitrate, the chief constituent of gun- 
cotton, 



32 THE MANUFACTURE OF PAPEE 

Charcoal. — Not a cellulose derivative in the strict sense of 
the term, charcoal being a residue obtained in the dry 
distillation of wood. 

Collodion. — A soluble nitrate of cellulose used in photo- 
graphy. (See Pyroxyline.) 

Cordite. — A smokeless powder consisting mainly of nitro- 
glycerine and gun-cotton mixed with acetone. The 
materials are thoroughly incorporated and the resultant 
paste formed into threads which are dyed and then cut 
up into suitable lengths for cartridges. 

Cuto-Cellidose. — Synonymous with adipo-cellulose. 

Dextron. — A compound prepared from the waste liquors of 
the bisulphite process used for the manufacture of wood 
pulp. Eesembles dextrin in its physical properties. 

Dextrose. — A carbohydrate which can be obtained by the 
action of mineral acids on cellulose. Commercial 
dextrose, or glucose, is prepared by the conversion of 
starch with sulphuric acid. The starch is mixed with 
dilute acid at a fixed temperature, and the starch milk 
obtained poured gradually into a vessel containing 
dilute acid, which is maintained at boiling point. The 
conversion is complete and rapid. 

Explosives. — The production of the several cellulose nitrates 
has given rise to a great number of highly explosive 
substances. 

Blasting Gelatine. — A mixture of nitro -glycerine with 
cellulose nitrates. 

Amherite, Ballistite, Cordite, and other smokeless 
powders, consisting of nitro-glycerine and cellulose 
nitrates in about equal proportions. 

Sporting poivders made by mixing nitro-cellulose with 
barium nitrate, camphor nitro-benzene, such as indurite, 
plastomenite, etc. 

Glucose. —(See Dextrose.) 



CELLULOSE AND PAPEE-MAKING FIBEES 33 

Gun-cotton. — An explosive prepared by the action of 
nitric acid on cotton. Selected cotton waste suitably- 
opened up is immersed in a mixture of three parts of 
nitric acid by weight (1-50 sp. gr.) and one part of 
sulphuric acid by weight (1-85 sp. gr.) and submitted 
to a number of processes by which the nitration is 
properly effected so as to produce a nitro-cellulose of 
uniform composition. The material is washed, reduced 
to pulp, and moulded into various forms. 

Hemi-Cellulose. — The constituents of plant tissues are 
extremely varied in character. Many plants contain 
substances which resemble true cellulose, but differing 
from it in being easily converted by hydrolysis, and by 
the action of dilute' acids, into carbohydrates. Plants 
which contain a large proportion of such constituents 
are termed hemi-celluloses. In some cases certain 
crystallisable sugars can be obtained by hydrolysis 
under suitable conditions. 

Hydral-Cellulose (Bumcke) . — A compound of merely scientific 
interest, resulting from the treatment of cellulose with 
hydrogen peroxide. When acted upon by alkali it is 
decomposed into cellulose and acid cellulose, the latter 
a derivative of unstable composition. 

Hydro-Cellulose. — This product, a white, non-structureless, 
friable powder, is obtained by treating cellulose with 
hydrochloric or sulphuric acid of moderate strength. 
The substance itself has no commercial value, but the 
reaction is useful in separating cotton from animal 
fabrics. If a woollen cloth containing cotton is soaked 
in dilute sulphuric acid, washed, and dried at a gentle 
heat, the cotton is acted upon, and can be beaten out 
of the fabric, the wool resisting the acid treatment. 

Lignin. — The complex mixture of substances which is 
associated with cellulose in wood, Jute, and other 



34 THE MANUFACTUEE OF PAPER 

ligno-celluloses. The conversion of wood into chemical 
pulp effects the removal of this material more or less 
completely. The well-known " phloroglucine " test 
for mechanical wood in papers is based upon the 
presence of lignin in the wood. 

Ligno-Cellulose. — Wood and jute are typical bodies con- 
sisting of cellulose and complex non-cellulose, gene- 
rally described as lignin, associated together in the 
plant tissue. The chemistry of the non-cellulose 
portion of wood is a matter still under investigation, 
its importance from a commercial point of view being 
obvious from the fact that the removal of the lignin 
during the conversion of the wood into wood-cellulose 
results in a loss of 50 per cent, of the weight of wood. 

Lustra-Cellulose. — Synonymous with and suggested as a 
more appropriate name for the material usually 
described as artificial silk. 

Mercerised Cotton. — When cotton is immersed in strong 
solutions of caustic soda a remarkable change sets in. 
The physical structure of the fibre is entirely altered 
from the long flattened tube having a large central 
canal to a shorter cylindrical tube in which the canal 
almost disappears. Hydration of the cellulose takes 
place, and these changes are taken advantage of in the 
production of mercerised cloth (so named from the 
discoverer of the reaction, Mercer). Cotton goods, 
particularly those made of long stapled cotton, when 
mercerised, exhibit a beautiful lustre, and some 
magnificent crepon effects are obtained by the process. 

Methoxyl. — A constituent of the complex compound known 
as ligno- cellulose, which is present in wood and similar 
fibres. The amount of methoxyl in lignified tissue can 
be accurately determined, and it has been suggested 
that the proportion of methoxyl found in a cheap 



CELLULOSE AND PAPER-MAKING FIBRES 35 

printing paper could be used as a measure of 
mechanical wood pulp present. 

Muco-Cellulose. — This term is applied to certain compound 
celluloses present chiefly in mucilages, gums, and in 
seaweeds (Algse). The natural substances are all of 
commercial importance — Iceland moss, Carragheen, 
Algin, etc. 

Nabhtha. — One of the products of the dry distillation of 
wood, usually described as wood-naphtha, or wood 
spirit. 

Nitro-Cellulose. — The treatment of cellulose with nitric 
acid gives a number of nitro-celluloses according to the 
conditions of the process. (See Cellulose Nitrates.) 

Oxalic Acid. — A substance of great commercial importance 
prepared by heating the sawdust of soft wood, such as 
pine, fir, and poplar, with strong solutions of mixed 
caustic soda and potash to dryness. The wood yields 
after six hours a grejash mass containing about 20 per 
cent, of the acid, which is separated out by water and 
then crystallised. 

It is used for bleaching, and as a discharge in calico 
printing and dyeing. 

Oxy -Cellulose. — A white friable powder produced by treating 
cellulose with nitric acid at 100° C. The oxidation of 
cellulose is brought about by several reagents such as 
chromic acid, hypochlorites of lime and soda, chlorine, 
and permanganates. The extent to which cloth has 
been damaged by overbleaching may be determined by 
a simple test with methylene blue solution, which is 
readily absorbed by oxy-cellulose present in such 
fabrics. 

Parchment. — A tough paj)er prepared by the action of 
sulphuric acid on unsized paper. (See page 187.) 

Pectins, — (See Pecto-Cellulose.) 

D 2 



36 THE MANUFACTURE OE PAPEE 

Pecto-Cellulose.—A generic term applied to many important 
fibrous materials, such as flax, straw, esparto, bamboo, 
phormium, ramie, &c., which on alkaline treatment 
yield cellulose for paper-making, and a non-fibrous 
soluble residue of complex composition. These soluble 
derivatives are known as pectin (C32 H48 O32), pectic 
acid (C32 H44 O30), and metapectic acid (C32 H28 Ose). 
Although the soluble constituents of the pecto-cellu- 
loses amount to 50 per cent, by weight in most cases, 
no process for the recovery of the product in a 
commercial form has yet been devised. (See descrip- 
tion of Soda recovery, page 78.) 

Pyroxyline. — A substance prepared by nitrating cotton. 
The cotton is immersed in a mixture of nitric and 
sulphuric acids of carefully regulated strength, and 
subsequently washed free of the acid. Three volumes 
of nitric acid (sp. gr. 1'429) are diluted with two 
volumes of water and nine volumes of strong sulphuric 
acid (sp. gr. 1*839) added. To the solution when cool 
the cotton is added in small quantities at a time. The 
resultant pyroxyline is soluble in a mixture of equal 
quantities of alcohol and ether, and in the soluble form 
is utilised as collodion for photography. 

Silk, Artificial. — A remarkable substance made from 
wood or cotton cellulose, closely resembling silk in 
appearance and physical properties. 

Nitrated cellulose is dissolved in a mixture of equal 
parts of alcohol and ether. 

The solution is forced through five capillary tubes 
under high pressure, and the filament so obtained 
solidifying at once is wound together with other 
similar filaments upon suitable bobbins. Various 
modifications of this general process are in use, such 
as the solidification of the solution into threads by 



CELLULOSE AND PAPER-MAKING FIBRES 37 

passing it into water ; the application of solvents less 
inflammable than ether and alcohol ; the use of other 
forms of dissolved cellulose such as those prepared by 
means of zinc chloride, ammoniacal copper oxide, or 
acetic anhydride. In all cases the yarn or thread 
is submitted to further chemical treatment for the 
removal of nitric acid and to render the material non- 
explosive and less inflammable. The finished product 
• is soft and supple, can be easily bleached and dyed, and 
is capable of acquiring a high lustre. 

Smokeless Powders. — (See Explosives.) 

Sulpho-Carhonate. — (See Viscose.) 

Sulphate Cellulose. — Chemical wood pulp prepared by 
the sulphate process. (See jpage 107.) 

Sulphite Cellulose. — Chemical wood pulp prepared by 
the sulphite process. (See page 107.) 

Viscose. — A soluble sulpho-carbonate of cellulose, prepared 
by treating cellulose with a 15 per cent, solution of 
caustic soda, and shaking the product with carbon 
bisulphide in a closed vessel. The mixture forms a 
yellowish mass soluble in water, giving a viscous 
solution which has some remarkable and valuable 
properties. 

This viscose, on standing, coagulates to a hard mass 
which can be turned and polished. 

If spread on glass and coagulated by heat, films are 
obtained from which the alkaline by-products can be 
washed out. These films are transparent, colourless, 
very tough and hard. 

Vulcanised Fibre. — Fibre or pulp treated with zinc 
chloride in acid solution, or otherwise, for the 
manufacture of hard boards. (See page 139.) 

Willesden Goods. — Paper, fibre, and textiles when treated 



38 



THE MANUPACTUEE OF PAPEE 



with cuprammonium oxide are partially gelatinised on 
the surface and rendered waterproof. (See page 139.) 

Wood Spirit. — (See Naphtha.) 

Xylonite. — (See Celluloid.) 

Fibres for Paper-making. 

Although the vegetable world has been explored from 
time to time for new supplies of cellulose, and some plants 
have been found serviceable in certain directions, yet the 
number of fibres in actual use is very limited. 

The following table indicates the principal sources of the 
material required for paper-making : — 



Fibre. 


Source of the Fibre. 


Application of the Fibre. 


Linen 


Eags, textile waste. 


High class writings and print- 


Cotton 


Eags, textile waste. 


ings. 
High class writings and print- 


Esparto . 


Natural grass. 


Writings and printings. 


Straw 


Straw from various 
cereals — wheat, bar- 
ley, oats, etc. 


Pi'intings, box and card boards. 


Wood 


Mechanically ground 


Cheap papers, boxboards. 




wood. 


middles, tickets and cards, 
writings and printings. 


>) 


Chemically prepared 


Writings and printings. 




wood. 




Flax 


Threads, waste from 


Wrappings, boards, cable 




spinning mills. 


papers. 


Hemp 


Spinning refuse, old 


Wrappings, boards, cable 




rope, sailcloth, etc. 


papers, strong writings. 


Jute 


Waste, old gunny bags. 


Wrappings, boxboard, cards. 


Bamboo . 


Natural stems. 


Writings and printings (not in 
Europe, and only limited 
quantities elsewhere). 


Eamie 


Bast fibres of the plant : 


Earely used, except in special 




textile refuse. 


cases. 


Bagasse . 


Sugar-cane refuse. 


Common papers (chiefly ex- 
perimental results). 


Manila 


Textile and rope refuse. 


Wrappings, cable papers. 


Hemp 







CELLULOSE AND PAPEE-MAKING FIBEES 39 

Exploiting New Fibres. — The exploitation of any new 
paper-making fibre requires attention to certain important 
details, which may be fairly considered in the following 
order : — 

(1) Supply. — The supply of material must be plentiful 
and obtainable in large quantities. Too often this question 
is entirely neglected by those who bring new fibres to the 
notice of paper-makers, probably because they do not 
reatise that enormous quantities of material are necessary 
to supply even a very small section of the paper trade, the 
fact being that few plants yield more than half their weight 
of paper-making fibre. 

(2) Suitability. — The fibre should be properly examined 
as to its chemical and physical properties in a laboratory 
equipped with appliances for its conversion into bleached 
paper pulp on a small scale. The examination of the fibre 
would include tests as to the amount of pulp which can be 
obtained from one ton of raw material, the approximate 
cost of treatment, and details as to the value of the fibre for 
paper-making. 

(3) Cost of Raw Material. — If the supply of material 
seems to be sufficient, and the paper pulp obtained possesses 
suitable qualities, then it is necessary to get accurate infor- 
mation as to the cost of the fibre delivered to some given 
spot at or near the place of collection. 

The exploitation of any new fibre for paper-making pur- 
poses will involve a recognition of the fact that the raw 
material must be converted into pulp at or near the place 
where the material is most abundant. 

The only interesting exception to this is the case of 
esparto fibre, which is imported into England in large 
amount, but this is only possible because esparto possesses 
most valuable paper-making qualities, and is obtained in 
countries close to England, where large quantities are 



40 THE MANUFACTURE OF PAPEE 

consumed. It is doubtful whether other fibres could be 
utilised in the same way. 

(4) Tlie Cost of Manufacture at or near the place of 
collection requires to be carefully worked out, due con- 
sideration being given to the actual cost of chemicals on the 
spot, cost of labour, and the conditions under which the 
maintenance of machinery can be efficiently looked after. 

(5) Carriage and Freight Charges are the last, but by no 
means the least, items of importance. It is not too much to 
say that the whole success of the exploitation of new paper- 
making fibre hangs entirely upon this item, the majority of 
many fibres which have been brought to the notice of the 
trade being suitable, but impracticable, solely on account 
of these and similar commercial considerations. 

In the pages of the trade press for the last few years the 
following fibres have been noticed : — 

(1) Flax Pulp. — This material was to be obtained from 
flax straw. Attempts were made on a commercial scale to 
produce quantities of flax fibre, but so far the efforts made 
have not been very successful. 

(2) Ramie Fibre. — This material has been exploited over 
and over again, chiefly for textile trades, its application as a 
paper-making material being limited to small quantities 
used for special purposes such as bank notes. The fibre is 
too valuable, except for textile industries, and can only 
come into the paper trade as a waste material from such 
sources. 

(3) Tobacco Fibre has been before the trade for some 
years, the idea being to utilise tobacco stems and other 
tobacco waste for the manufacture of paper suitable for use 
as wrappers for cigars, cigarettes, and similar purposes. 

(4) Agave Fibre, — This name is given to a large and 
important genus of fibre-yielding plants found chiefly in 
Central America. It is also found in India, and in 1878 an 



CELLULOSE AND PAPEE-MAKING FIBEES 41 

experiment was made for the manufacture of paper at a 
mill near Bombay, but this did not give any satisfactory 
results, probably on account of the primitive methods used 
in treatment. 

(5) Bagasse. — The waste material from sugar-cane has 
been looked upon for many years as a desirable fibre, much 
time and labour having been given to the utilisation of this 
material. In spite of these efforts bagasse still remains an 
alnffost useless and unworkable material. This is partly 
due to inferiority of the pulp and partly due to difficulties 
connected with its treatment. Probably cultivation of the 
plant for the sake of its fibre instead of the sugar might 
give better results. 

(6) Peat. — The attempts made to utilise peat for paper- 
making are probably fresh in the minds of those paper- 
makers interested in the production of wrappers and 
boxboards. The nature of peat, however, is such as to 
exclude the hope of making any useful article. The material 
has been exploited by companies in Austria, Ireland, and 
Canada on a fairly large scale, with but a limited amount 
of success. 

(7) Cotton-seed Hulls. — Many patents have been taken 
out for the chemical treatment of cotton-seed waste and 
having for their object the removal of the particles of seed 
hulls, so as to obtain a pure cotton pulp. The scheme 
sounds attractive, but there are so many conditions which 
have to be taken account of that the commercial success of 
any undertaking based on the use of cotton-seed hulls is 
very questionable. The fact is that the hulls have a 
market value quite apart from the possibility of their 
application to paper-making, and this initial cost would 
prevent paper-makers from buying the material owing to 
the large quantity necessary for the manufacture of one ton 
of pure pulp. 



42 THE MANUFAOTUEE OF PAPER 

(8) Apocynum. — This plant is said to be utilised to some 
extent by the Eussian Government in the manufacture of 
bank notes, the plant being cultivated at Poltava. This 
is an instance of the particular application of a fibrous 
material in limited quantities, a proposition which is 
always feasible in the case of special requirements. 

(9) Cornstalk.— Hhi^ fibre has been chiefly exploited in 
America, experts having been attracted by the enormous 
quantities of cornstalk available in the several wheat- 
producing States. The manufacture of paper pulp from 
this material on a large scale has yet to be established. 

(10) Japanese Paper Fibres. — In Eastern countries a 
great number of fibrous plants are utilised in small quanti- 
ties for the manufacture of special papers. It is obvious 
that in these Eastern countries the employment of fibres 
which are not cultivated in large bulk is readily possible 
when the question of price obtained for the paper and the 
cost of production are considered. Of such fibres may be 
mentioned the Mitsumata and Koclzu, easy of cultivation and 
giving a good yield of material per acre of ground. The 
waxed papers used for stencils in duplicating work on the 
typewriter are made from these fibres. The paper Mul- 
berry is also a well-known fibre ; while a third species 
particularly valuable for thin papers is the Gampi. 

(11) Antaimoto Fibre. — The bark of this shrub is utilised 
in Madagascar in very small quantities for local purposes 
and possesses little interest for paper-makers. 

(12) Refuse Hempstalk. — The suggestion of the use of 
this material comes from Italy, the hempstalk having been 
experimented with at San Cesario Mill. This also is a fibre 
of a local interest only. The percentage of cellulose is very 
high, being over 50 per cent. 

(13) Papyrus. — The revival of this celebrated material is 
of comparatively recent date. It should be noted that the 



CELLULOSE AND PAPER-MAKING FIBEES 43 

manufacture of papyrus as carried out by the Egyptians, by 
smoothing out layers of bark in order to utiKse them as 
sheets of paper, and the present day proposals which involve 
the production of paper pulp from papyrus, are two entirely 
different propositions, and the success of the old Egyptian 
method cannot be referred to as any assurance of success 
for the production of paper from papyrus along modern 
lines. The exploitation of this fibre must follow the 
lines of modern research and commercial investigation, 
and its value, if any, could then be established. 

(14) Pousolsia. — This is a fibre of the same family as 
hemp and ramie. The value of this material is at present 
unknown, but the ultimate fibre appears to possess a most 
extraordinary length. Very little information is available 
at present as to its value for paper-making. 

(15) Bamboo. — This material has been before the paper 
trade for many years, having first been exploited seriously 
by Mr. Thomas Eoutledge in 1875, Since that date a good 
deal of work has been done in connection with the fibre, but 
not until recently has the investigation been made of a 
sufficiently extensive character to enable paper-makers to 
form some conclusions as to the best methods of obtaining 
a reliable paper pulp. The researches of the writer in India 
go to prove that with any fibre it is necessary to take into 
account all the factors likely to affect the final cost of the 
paper pulp delivered to any given paper mill. 

The figures given in a report recently published, " The 
Manufacture of Paper and Paper Pulp in Burma," show the 
necessity of thorough investigation into all the points likely 
to affect the final results, viz., the price at which the paper 
pulp can be sold in England, assuming that the fibre in 
question is suitable for the manufacture of paper. 

Examination of Fibres. — The exact chemical analysis of 



44 THE MANUFACTURE OF PAPER 

a new fibre is necessary in order to establish completely 
its value for textile and paper-making purposes, but the 
investigation of the suitability of the fibre for paper-making 
may be simplified by simple reduction of the raw material 
with caustic soda. The following process is sufficient for all 
practical purposes : — 

Condition of Sample. — A record should be made of the 
general appearance of the sample, its condition and the 
amount available for the investigation. Any information 
available as to the source of supply and the growth of the 
plant should also be noted. 

Preparation of Sample. — The material is cut up into 
small pieces. The most convenient appliance for this pur- 
pose is a mitre cutter as used by picture-frame makers. If 
the sample is a piece of wood, sections one inch thick cut 
across the grain of the wood are most suitable, as they can 
be readily cut up into thin flakes by this machine. 

Moisture in Sample. — A small average sample should 
be dried at 100° C. for the determination of moisture. 

Treatment ivith Caustic Soda. — About two hundred grams 
of the raw material is closely packed into a small digester 
or autoclave and covered with a solution of caustic soda 
having a specific gravity of 1"050. A perforated lead disc 
should be placed above the sample in the digester to prevent 
any of it from floating above the level of the solution. The 
material should be digested for five or six hours at a 
pressure of 50 lbs. The conditions of treatment here given 
will need to be varied according to the nature of the fibre. 
Some materials can be readily converted into pulp with 
weaker liquor and at a lower pressure, while others will 
require prolonged treatment. These conditions must be 
varied according to judgment or according to the efi:ects 
produced by the conditions already set out. 

Unhleaclied Pulp. — The contents of the digester are 



CELLULOSE AND PAPEE-MAKING FIBRES 45 

emptied out into an ordinary circular sieve provided with 
a fine copper wire bottom, having a mesh of about sixteen 
to the inch. The sieve is immersed in water and the con- 
tents partially washed with hot water. The partially washed 
material is squeezed out by hand and tied up in a strong 
cloth and then kneaded thoroughly by hand in a basin 
of water which is repeatedly renewed until the fibre is 
thoroughly washed. The process of kneading at the same 
time reduces the fibre to the condition of pulp. The water is 
carefully squeezed out of the pulp by hand, and the moist 
pulp is then divided into two equal parts, the first of which 
is made up into sheets of any convenient size, care being 
taken that none of the fibre is lost. These sheets are then 
dried in the air and preserved as samples of unbleached 
pulp, a record being made of the weight produced. 

Bleached Pulp. — The second portion of the moist pulp is 
mixed with a solution of bleach, the strength of which has 
been accurately determined by the usual methods. The 
amount of bleach added should be about 20 per cent, of the 
weight of air-dry fibre present in the moist sample of pulp. 
The pulp should be bleached at a temperature not exceeding 
38° C, and when the colour has reached a maximum the 
amount of bleach remaining in solution is ascertained by 
titration with standard arsenic solution. In this way the 
amount of bleaching powder required to bleach the pulp is 
determined. The product is then made up into sheets of 
pulp which are dried by exposure to air and subsequently 
weighed. 

Yield of Pulp. — The percentage yield of finished pulp 
obtained from the raw material is determined from the 
figures arrived at in the experiment described, and the 
weight of raw material necessary to produce one ton of 
bleached pulp is readily calculated. 

Examination of Bleached Fibre. — The fibre should be 



46 THE MANUFACTUEE OE PAPEE 

carefully examined under the microscope and a record 
made of general microscopic features, especially with refer- 
ence to the length and diameter of the fibres, and the 
proportion of cellular matter present, if any. 

Samjjle of Paper. — It is only in the case of short-fibred 
material similar to esparto and straw that sheets of paper 
callable of giving comparative results as to strength can be 
made. The figures obtained with fibrous materials of this 
kind are only comparative, because it is possible in practice 
to make a much stronger sheet of paper when the material 
is beaten properly under normal conditions. 

A similar investigation should be made by submitting the 
fibre to treatment with bisulphite of lime, that is to say, if 
the fibre lends itself to such a process. A lead-lined digester 
is necessary, and the solution employed is bisulphite of lime 
prepared according to the directions given on page 160. 

The preparation of sulphite pulp requires more attention 
than the manufacture of soda pulp. It is most important that 
the digester should be absolutely tight in order to prevent 
the escape of any free sulphurous acid gas, and the contents 
of the digester must be heated slowly until the maximum 
pressure has been reached. 



CHAPTEE III 

THE MANUFACTURE OF PAPER FROM RAGS 

T^E word rag is used to designate a very wide range of 
raw material suitable for conversion into paper. In the 




Pig. 6. — ^A Bag Sorting House. 

case of high-class hand-made writing papers only the best 
qualities are employed, such as new linen and cotton 



48 



THE MANUFACTUEE OF PAPEE 



cuttings from factories, or well-sorted rags of domestic 
origin. The usual classification adopted by merchants 
who supply the paper mills is somewhat as follows : — 

New white linen cuttings (from textile factories). 

New white cotton cuttings (from textile factories). 

Fine whites (domestic rags). 

Outshots (a quality between fines and seconds). 

Seconds (a grade inferior to fines). 

Thirds (inferior and dirty well-worn rags). 

Coloured prints (of all grades and colours). 

Fustians and canvas. 

Manila and hemp rope. 

Baggy, gunny, and jute. 
The total amount of rag used in England for paper- 
making is not known. The only figures available refer 
to rags imported; and these cannot be regarded as a measure 
of consumption, which could only be arrived at by first 
ascertaining the quantity of home rags used. The imports 
of rag at stated periods are given in the appended table : — 

Eags Imported into England. 



Weight (tons) . 
Value 



1872. 


1882. 


1892. 


1902. 


22,254 
£373,035 


21,200 
£303,349 


23,032 
£214,065 


18,692 
£173,732 



23,681 
£224,232 



Sorting and Cutting. — All rags on arrival at the mill are 
carefully sorted. This process is conducted entirely by 
women, who sort and cut up the rags at special tables 
provided with cutting knives curved in shape similar to a 
scythe. These are fixed at an angle in the centre of the 
table, with the back towards and in front of each work- 
woman. The top of the table is made of thick coarse wire 



THE MANUFACTUEE OF PAPER FROM RAGS 



49 



SO that some of the dirt and foreign impurities may fall 
through. All buttons, hooks and eyes, pins, leather, pieces 
of rubber, and other articles are carefully removed, while 
seams and hems are also opened out. The rags are cut into 
slips 3 — 5 inches long and then recut crosswise, and thrown 
into suitable baskets or receptacles standing round the 




Fig. 7. — A Rag Duster. 

table, by which means the sorting operation is effectually 
carried out. The care and attention given to the sorting is 
an important item in the manufacture of papers of uniform 
quality, and in the best mills the sorting is carried out 
to such an extent that twenty or twenty-five grades are 
obtained. 

Dusting. — The rags are next passed through a machine 
which removes dirt. This is a hollow cylindrical or conical 

p. E 



50 



THE MANUFACTUEE OF PAPER 



drum having an external covering of coarse wire cloth, 
which rotates inside a wooden box. The shaft is provided 
with projecting spikes, so that the rags are violently 




Fig. 8.— a Eag Cutter. 

agitated in their passage through the machine. The dirt 
and other impurities fall through the wire on to the floor 
of the room, while the clean rags are discharged from the 
lower end of the drum. The loss in weight varies according 
to the condition of the rags. With good materials the loss 



THE MANUFAOTUEE OF PAPER FEOM RAGS 51 

may only be 1 — 2 per cent., while with dirty common 
rags the loss during cleaning and dusting may amount to 
10 per cent. 

Boiling. — The further purification of the rags is effected 
by a chemical treatment, viz., boiling at a high temperature 




Fig. 9. — Interior of Paper Mill for Hand-made Paper 
(R. Batchelor & Sons). 

with alkaline substances, which process removes fatty, 
glutinous, and starchy matter from the material. 

For this purpose a spherical digester is used, generally 
7 — 9 feet diameter, and capable of holding 2 — 2J tons of 
rag. The boiler or digester is filled with dusted rags, and 
the requisite amount of alkaline solution added. The man- 
hole is then closed, and steam admitted through the hollow 

B 2 



52 



THE MANUFACTUEE OF PAPER 



trunnions until the pressure reaches 20 or 30 lbs., at which 
pressure the boiling is continued for three to six hours 
according to requirements, the digester rotating slowly the 




Fig. 10. — View of a Rag Boiler, showing connections. 

whole time in order that the rags may be evenly and 
thoroughly boiled. 

The liquor employed for boiling is a solution of caustic 
soda, carbonate of soda, or milk of lime. In the case of 
caustic soda the amount required varies from 5 to 10 per 
cent, of the weight of rag. Caustic soda is preferable to 
lime, because it acts u]3on the grease and other fatty 



THE MANUFACTUEE OP PAPEE FEOM EAGS 53 

matters, forming a soluble compound which is freely 
removed in the subsequent process of washing. Many 
paper-makers, however, use milk of lime, carefully strained 
through fine cloth, almost exclusively. Considerable expe- 
rience and skill are necessary in this operation in order 
to avoid injury to the fibre not only as regards its strength, 
but also its colour. 

Washing. — When the rags have been sufficiently boiled, 
the^team is turned off and the pressure allowed to fall. 
This can be effected quickly by blowing off from a valve 
fixed at the bottom of the boiler opposite to the manhole. 
The cover is removed from the boiler and the boiler slowly 
rotated in order that the contents may be discharged into 
a tank placed below. The " black liquor," as it is called, 
is then drained away from the rags, which are immediately 
subjected to a preliminary washing. The process of washing 
must be carried out in a thorough manner in order to 
remove all soluble compounds, which if left would cause an 
unnecessary waste of bleach in the subsequent stages of 
purification. There are many schemes employed for 
washing, most of them being devised with the idea of 
using a minimum quantity of water. 

The most general practice, in the absence of special 
machinery, is the preliminary treatment in the tank below 
the digester, followed by a more complete washing process 
in a machine known as a breaking engine. 

This apparatus is a shallow oval- shaped vessel with 
circular ends, divided lengthwise by a partition called a. 
mid-feather, which, however, does not extend the full length 
of the apparatus. In one of the two channels into which 
the vessel is thus divided a heavy roll is fitted, which is 
provided with a number of steel knives. On the floor of 
this channel there is fixed a "bed-plate," also provided 
with projecting knives which are parallel with the knives 



54 



THE MANUFACTUEE OF PAPEE 



in the roll. The distance between the knives in the roll 
and those in the " bed-plate" may be altered as required 
by means of an adjusting screw. In the other channel of 
the breaking engine there is fitted a " drum-washer," which 
serves for the removal of the dirty water from the machine. 
This drum is divided into sections by means of partitions 
which reach from the centre to the circumference. The 




Fig. 1 1 . — A Breaking and Washing Engine. 

surface of the " drum-washer " consists of a fine brass wire 
cloth supported by a coarser material placed underneath. 

The breaking engine is half filled with clean water, and 
the rags are thrown into the engine until it is suitably 
filled. The rotation of the heavy roll causes the mixture 
of rags and water to circulate round the vessel, the floor of 
which is so constructed that the pulp is drawn between the 
roll and " bed-plate " and discharged over the " back-fall," 
which is that portion of the sloping floor behind the 
*' bed-plate." 



THE MANUFAOTUEE OF PAPEE FEOM EAGS 55 

The " drum-washer " rotates with its surface in contact 
with the mixture in the engine, so that the dirty water 
passes through the wire cloth and is caught in the curved 
sections or buckets inside the drum and discharged into a 
trough adjacent to the centre, and thereby conveyed away 
from the engine. Clean water is allowed to run into the 
vessel at one end while the dirty water is discharged by 
means of the " drum- washer." At the same time the rags 
are !5roken up by means of the knives on the roll, so that when 
the rags are sufficiently washed, a process which usually 
occupies four hours, they are also partially disintegrated. 

Bleaching. — The clean disintegrated rag is next bleached 
by means of ordinary bleaching powder solution. Bleaching 
powder is a substance prepared by the action of chlorine 
gas on dry slaked lime, resulting in the formation of a com- 
pound which has the property of bleaching or *' whitening" 
vegetable matters. The clear solution obtained by treating 
the powder with water is utilised by the paper-maker for 
bleaching the rag pulp. 

Various methods are used for this purpose. Sometimes 
the requisite volume of clear bleach liquor is added to the 
pulp in the breaker, and the material kept in constant 
circulation until the operation has been completed. In 
other cases the broken pulp is transferred to a "potcher," 
which is a vessel similar in shape to the breaker, but merely 
provided with paddles for keeping the pulp in circulation, 
and bleached by the addition of chloride of lime solution. 

Another method frequently adopted is to discharge the 
pulp from the breaker, immediately after the addition 
of the bleach, into brick or cement tanks, allowing the 
bleaching action to proceed spontaneously without pro- 
longed agitation. 

In some instances the process is hastened by adding 
dilute sulphuric acid to the pulp after the bleach liquor has 



56 THE MANUFACTUEE OF PAPER 

been run in, or by heating the mixture with steam. For 
high-class papers such devices as this are seldom resorted 
to, as experience shows that the colour of pulp bleached by 
drastic methods does not maintain a high standard. 

The pulp is then thoroughly washed in order to remove 
every trace of residual bleach, and also the soluble com- 
pounds which have been formed during the operation. 
Very large quantities of water, clear and free from suspended 
dirt, are necessary. In some mills any excess of bleach is 
neutralised by the use of an " antichlor " such as sodium 
hyposulphite, or sodium sulphite, but the best results are 
undoubtedly obtained when the quantity of chemicals 
used is kept at a minimum. 

If the pulp is bleached in a breaker or potcher, the wash- 
ing is effected by the aid of the drum-washer. With pulp 
treated in steeping tanks, fresh water is allowed to percolate 
or drain slowly through the mass. 

Electkolytic Bleaching. 

The substitution of a sodium hypochlorite solution for 
the ordinary calcium hypochlorite solution obtained from 
common bleaching jDOwder has been the aim of specialists 
for many years. As early as 1851 a patent was taken out 
by Charles Watt for decomposing chlorides of the alkali 
metals and the formation of hypochlorites. It was not 
until 1886 that a practical method was devised for producing 
an electrolysed solution of salt, but in that year Hermite 
introduced a continuous process in which an electrolysed 
solution having a strength of three grammes chlorine per 
litre was passed continuously into the potcher. 

Many patents for the electrolysis of salt have been taken 
out during the last twenty years, of which the Bird- 
Hargreave process is in operation in England, the Ehodin 
process in America, the Siemens and Halske in Norway, 



ELECTEOLYTIC BLEACHING 



o/ 



and the Oettel and Haas apparatus in Germany. The 
figures relating to the latter apparatus may be mentioned 
as typical of the present condition of electrolytic bleaching. 
The apparatus consists of a narrow rectangular trough 
divided into a number of chambers through which a solution 
of brine flows at a constant and steady rate. The electric 
current is passed through the solution by suitable electrodes, 
the temperature being kept down by means of a cooling 
coiT. The cost of producing the bleach liquor as given by 
tlie inventors of the apparatus from the results of actual 
working are shown in the following table : — 

Table giving Analysis of Cost por Producing Bleach 
Liquor. 

Capacity of tank . . . 750 litres = 166 gallons. 
Strength or density of brine . I'o Beaume, or 2'i Twaddell. 
286 lbs. of common salt required for 166 gallons. 



Hours worked 


2 


4 


6 


8 


10 


12 


Grammes of chlorine 














per litre produced 


4-35 


7-38 


9-9 


12-42 


14-31 


16-20 


Temperature C. of 














brine during 














operation 


20 


21 


20 


21 


20 


20 


Amperes of 110 volts 


55 


50 


46 


52 


47 


43 


Power in h.p. hours 


16 


31 


45 


61 


75 


89 


Cost of the h.p. at 














•22d. per h.p. 














hour . 


^d. 


6^d. 


lOd. 


Is. l^d. 


Is. 4K 


Is. Ud. 


Cost of salt 


Is. 6d. 


Is. 6d. 


Is. 6d. 


Is. 6d. 


Is. U. 


Is. Qd. 


Total cost 


Is. 9^d. 


2s.0|d 


2s. 4d. 


2s. l\d. 


2s. I0\d. 


3s. IJcZ. 


Total chlorine ob- 














tained in kilos. 


3-262 


5*535 


7-425 


9-315 


10-732 


12-150 


Cost of chlorine per 














kilo. . 


6-6c^. 


i^d. 


3|d 


3-4r?. 


3-2c?. 


3c?. 


Salt used per kilo. 














chlorine 


35 


20 


15 


12 


10 


9 



The above costs have been estimated on prices as follows : — 

Coal . . .10s. per ton. 

Salt , . .12s. per ton. 

After 12 hours the 166 gallons (750 litres) are converted into electro- 
lytic bleach liquor containing 26| lbs. of active chlorine (12-15 kilos.). 



58 



THE MANUFACTUEE OF PAPER 



Beating. — Although the rags are reduced by the breaking 
engine to a condition of fibrous hnt, called " half-stuff," 
they are not fit for conversion into paper. They have to 
be beaten in special machinery until a complete separation 
of the single fibres has been effected, and this process is 




Fig. 12. — Oettel and Haas' Apparatus for the manufacture of 
Electrolytic Bleach. Liquor. 

rightly regarded by many paper-makers as the most 
important stage of manufacture. 

The beating engine is similar in construction to the 
breaking engine, but there are certain essential differences 
in arrangement and manipulation. There is usually no 
drum-washer ; the roll contains a large number of knives 
which are fixed in clumps or sets of three round the 
circumference ; the lowering of the roll upon the bed-plate 
is carefully watched and controlled, and the desired effects 



BEATING 



59 



are only obtained by strict attention to the condition of the 
pulp during the whole process. 

The beater is first partially filled with water, and the 
drained half-stuff added gradually until the " furnish," a 
convenient term applied to the contents of the engine, has 




i^'iG. 13.— The *' Hollander" Beating Engine. 

the proper consistency, which varies according to the nature 
and quality of paper required. 

The mass is circulated steadily round the engine by the 
action of the beater roll, which is lowered from time to time 
until the distance between the knives on the roll and those on 
the bed-plate has been set to the desired adjustment. This 
lowering of the roll and its proper adjustment call for the 
greatest care. 

Influence of the Beating. — The imiDortance of this opera- 
tion can easily be judged from one or two specific examples. 



60 THE MANUFACTUEE OF PAPEE 

In the case of rag papers the two extremes of variation are 
represented by the ordinary blotting paper on the one 
hand and a hard strong writing paper known as a loan on 
the other. Now the great difference in these papers maybe 
traced to the careful selection of the rag and the treatment 
in the beater as the two primary causes of the final 
results. 

For blotting j^apers it is essential that the rags should 
be old and tender. In the beating operation subsequent to 
the usual boiling and bleaching processes the half-stuff is 
beaten quickly with sharp knives, the roll being lowered 
soon after the engine is filled, so that the beating is finished 
in about one to one and a half hours. 

For the strong writing paper new strong rags are selected. 
In the beating process the knives used are dull, the roll is 
lowered slowly and cautiously, and the beating goes on for 
eight to ten hours. 

The effect of such difference in treatment is easily seen 
by examination of the fibres of the papers under the micro- 
scope. In the first case the fibres appear short with clean 
cut ends, the shape little distorted, the structure well 
defined, bearing a strong resemblance to the unbeaten 
material. In the case of the well-beaten paper the ends of 
the individual fibres appear to be drawn or frayed out, 
the fibres do not possess the sharp well-defined outline 
characteristic of blotting paper; they are partly split up 
into fibrillse which lie together in a confused mass. 

In the blotting paper these effects are produced because 
the knives being sharp cut up the material quickly, and 
in the writing pajDer because the dull "tackle" tends to draw 
out the fibres and tear them up lengthwise. 

The practical result is a sj)ongy, soft, and bulky blotting 
and a hard, strong, heavy writing paper. Of course the 
great difference between a blotting and a writing paper is 



BEATING 



61 



not all due to this one operation, but is obtained by a series 
of operations, of which one of the most important is, how- 
ever, the beating. 

Colouring the Paper. — The pulp is brought to any desired 
tint by the addition of mineral pigments or anihne dyes to 
the contents of the engine. The latter soluble dyes, however, 
are seldom used for high-class rag papers. Prussian blue, 
ultj;amarine, and smalts are chiefly used for this purpose, 
giving toned blue, azure, and blue laid papers. 

Making the Paver. — The beaten pulp, when duly prepared, 
is run from the engine into 
store tanks known as stuff 
chests, ready for the actual 
manufacture. The pulp pro- 
perly diluted with water is 
strained through special 
screens to remove any in- 
sufficiently beaten material 
and any impurities jDresenc, 
after which it is run off into 
the vat, a square-shaped 
vessel built of wood or stone. 



^<^ 




Pig. 14.— The Hand Mould 
showing Frame and Deckle. 



The apparatus used in forming the sheets is called a 
hand mould. The mould is a rectangular frame of mahogany 
uj)on which is stretched tightly a fine wire cloth, the surface 
of the latter being kept flat by a coarser wire cloth fixed 
underneath, supplemented by wedge-shaped pieces of wood. 
A second frame called the deckle fits on to the mould in such 
a manner as to form a shallow tray, the bottom of which is 
the fine wire cloth. 

The vatman takes up the mould with both hands and 
dips it into the vat full of pulp in a slanting position, draw- 
ing it through the stuff towards him in a peculiar manner 
and lifting it out from the vat with a definite quantity of 



62 THE MANUPACTUEE OF PAPEE 

the mixture in the frame. As the water drains away from 
the pulp, through the wire cloth, he imparts a shaking 
motion to the mould in order to cause the fibres to " felt " 
properly, this felting or interlacing of the fibres being an 
essential feature in the manufacture of a good sheet of paper. 
When the water has drained away sufficiently from the 
pulp, the vatman removes the deckle from the mould and 
passes the latter over to the coucher, who takes the mould, 
reverses it, and presses the contents, which may now be 
described as a wet sheet of paper, down on to a damp piece 
of felt, by which means the paper is transferred to the felt. 
He returns the mould to the vatman, who meanwhile has 
made another sheet with a duplicate mould, and then, having 
laid a second felt upon the wet sheet of paper, he proceeds 
to transfer the next sheet of paper to the second felt. This 
process is continued until a pile is formed consisting of wet 
sheets of paper alternated with pieces of felt. 

The pile is at once submitted to great pressure in the 
hydraulic press, and the excess water slowly forced out, 
while at the same time the sheets are compressed and thus 
"closed up," as it is termed. "When all the excess water 
has been removed as far as possible, the pile is taken away 
and the sheets of damp paper taken out, the felts being 
placed in one pile ready for further use, and the sheets of 
paper in a second ready for the next process. 

The papers are put back into the press without felts 
between the sheets and left for some time. In most cases 
the sheets are turned round or mixed in with the sheets of 
another pile, before pressing. In this way any unevenness 
or irregularity in the sheets is counteracted and a more 
uniform result obtained. 

"When these changes are repeated several times the paper 
acquires an even texture and becomes firm and hard. 

Drying the Paper. — The sheets are hung up in the loft, 



SIZING 



63 



as the drying room is called, upon poles or ropes. The 
moisture gradually evaporates, and the ]_3ai3er is thus dried 
by exposure to air. In winter it is necessary to warm the 
air in the loft, as the air is then saturated with moisture. 
In lofts of limited capacity the air is heated in order to 
hasten the process, but the best paper is allowed to dry 




Fig. 15. — Apparatus for Sizing Paper in continuous EoUs. 

naturally, as by this means the shrinkag;e is gradual and a 
maximum strength is attained. 

Sizing the Paper. — The dried paper as it leaves the loft 
is termed Waterleaf because, being unsized, it readily 
absorbs water, and therefore before it can be used it must 
be sized. For this purpose it is dipped into a solution of 
gelatine, an operation described as tuh-sizing or animal- 
sizing, the former term being used on account of the tub in 
which the size is kept, and the latter on account of the fact 
that the gelatine is made from animal matter such as hides, 
cartilage, hoofs, and other refuse. 

Animal Size.— Thi^ is prepared from hide pieces, skins, 



64 THE MANUFACTURE OF PAPER 

and the like by a simple process, which, however, requires a 
good deal of care in order to obtain the best results. The 
material is first thoroughly washed in plenty of clean water, 
and then heated with a definite quantity of water in a 
steam jacketed copper pan. The pieces slowly dissolve 
until a solution of gelatine is produced, and after the dirt 
and impurities have settled to the bottom of the pan the 
clear liquid is drawn off into store vessels. There are many 
details of a technical character to be attended to in the 
manufacture of good gelatine, and as the process is expen- 
sive, considerable attention is demanded at this stage in the 
completion of a sheet of paper. 

The dry sheets of paper are sized by the simple expedient 
of dipping, or by the passage of the paper through a long 
trough. In the first case the workman takes up a number of 
sheets and dips the bunch into a vat of size at the proper 
temperature, about 100° Fahrenheit. He then allows the 
surplus size to drain off, and the sheets are submitted to a 
slight pressure in order to remove the excess of gelatine that 
will not drain off. 

In the second case a different method is adopted in that 
the sheets of paper are carried by travelling felts through a 
bath of heated size, the excess gelatine being removed by 
the action of rubber or wooden rollers through which the 
papers are passed before leaving the apparatus. The papers 
are quickly and evenly sized by this method, which is now 
most generally used. 

Glazing.— When the sheets of paper are quite dry they 
are Yeadj for glazing, a process which turns the dull rough 
surface of the sized sheet into a highly polished smooth 
surface fit for use. The sheets are placed singly between 
copper or zinc plates, and a pile of these passed several 
times through heavy iron rollers, great pressure being 
applied to the latter during the operation. 



SIZING 



65 




Fig. 16. — A Supercalendei 



66 THE MANUFACTUEE OF PAPER 

The amount of polish imparted by this plate-glazing pro- 
cess, as it is termed, can be varied considerably. With a 
light pressure and few rollings, the sheet of paper can be 
turned out having a fairly smooth surface, and without a 
conspicuously shiny appearance. By employing a great 
pressure and repeated rolling a much higher surface is 
attainable. If the plates are hot a still higher finish is 
possible. Machine-made rag papers are glazed usually by 
means of the supercalender, which is a stack of alternate 
steel and paper rolls placed one above the other in a 
vertical position. The reel of paper passes between these 
rolls and becomes highly surfaced. 

This operation effects many changes in the paper, besides 
imparting a good finish. The thickness of the sheet is 
reduced by about 40 per cent., the fibres being compressed 
much closer together. The tensile strength of the paper is 
also materially increased, and in every way the paper is 
improved. Moderation is essential in this as in everything, 
because excess of glazing weakens a paper, rendering it 
brittle and liable to crack when folded. 

Laid and Wove Papers. — When certain papers are held 
up to the light and carefully examined it will be noticed 
that they appear to contain delicate transparent lines 
running parallel with one another at equal distances of 
about an inch, and that these are intersected by similar 
transparent lines running at right angles, which are much 
closer together. Such papers are known as Laid Papers, 
and the peculiar formation of the transparent lines is due 
to the construction of the mould used in the making. The 
wire surface of this mould consists of a number of some- 
what stout wires placed about one inch apart, interwoven 
with finer wires running across and at right angles, which 
are threaded much closer together. When the mould is 
dipped into the vat and withdrawn, the water drains away 



WATEEMAEKS 67 

from the under surface of the wire, and the moist pulp 
settles down on the upper surface ; but since the coarser 
wires project a little from the finer threads, the paper is 
slightly thinner along those wires, though to an almost 
infinitesimal extent, with the result that on drying the 
sheet appears to contain transparent lines. 

Wove papers are so called from the nature of the mould 
used. The surface of the mould in this case 
consists of fine wires equally distributed, being ^ 

woven in such a manner that the wires are 
equidistant from one another, as in ordinary 
wire gauze. A wove paper, on being examined 
in the light, simply shows a number of small 
diamond-shaped spaces, which in the majority 
of instances are difficult to detect. 

The Watermark. — The transparent device 
observed in many papers when held up to the 
light is known as the watermark, a term pro- 
bably derived from the conditions existing at 
the time the sheet of paper is made on the 
mould. The effect is produced by means of 
a raised design sewn or soldered to the surface i,?' , ^TT, 

First vv SitGr- 

of the mould, the design being fashioned out mark in 
of fine wire. Paper. 

When a mould thus fitted with the design is 
dipped into a vat of pulp and lifted out, the water falls 
through the wire, and the pulp sinks down on to the surface 
of the mould, forming a replica, so to speak, of the design, 
which is easily seen when the dry paper is held up to the 
light, because the paper is thinner just at those points 
where the wires forming the design come into contact with 
the wet pulp. 

Some of the watermarks are very elaborate and interesting. 
A familiar illustration of a beautiful design of this 

F 2 




68 THE MANUFACTUEE OE PAPER 

description is to be found in the Bank of England notes. 
As a general rule the ordinary watermark consists of a 
mere trade term such as "Vellum," " Zenobia," or of the 
name of the manufacturer, such as " J. Whatman," 
" R. Batchelor," and so on. In the earlier days of paper- 
making many highly interesting designs were used, and 
some of these are still extant. In fact many of the names 
by which certain standard sizes of paper are known owe 
their origin to the watermarks employed. 

The earliest known watermark bears the date a.d. 1301, 
being in the form of a globe and cross, as shown. Of equal 
interest are those designs from which certain papers are 
called foolscap, crown, pott, post, royal, columbier, and so 
on. The watermarks are now little used, but the terms are 
still retained, as indicating the size of the sheet. 



Microscopic Features of Cotton and Linen Fibres. 

The cotton fibre is about 30 mm. long, with an average 
diameter of "025 mm. of tube-like shape, and having a 
prominent central canal. There are no cross markings 
on the cell walls, and the ends of the fibre are rounded 
off into a somewhat blunt point. It exhibits a marked 
tendency to twist itself, especially if dry, and this 
peculiarity is readily observed with the raw material. 

The process of paper-making alters the characteristic 
structure of the fibre very greatly. The ends of the fibre are 
seldom to be seen ; the curious twist is less prominent, and 
the fibres are torn and destroyed. The effect of the beating 
process, for example, on cotton is easily to be noticed by 
comparing the fibres of a blotting paper under the microscope 
with the fibres of a hank or Zoaw paper. 

The distortions produced by prolonged beating renders 



COTTON AND LINEN FIBEES 69 

the determination of the exact percentage of cotton in a rag 
paper rather difficult, but the features to be looked for are 
the absence of pores, cross markings, the existence of a 
central canal, striations produced in many cases on the cell 



Fig. 18.— Cotton. 

walls parallel to the length of the fibre. The structural 
features are more readily observed when the fibres are 
stained with a suitable reagent. (See page 71.) 

The linen fibre has an average length of 27 mm. with a 
diameter of "02 mm. The raw flax is very different from raw 



70 THE MANUFACTURE OF PAPER 

cotton and is easily distinguished. The fibre is slender in 
shape, having thickened knots at regular intervals through- 
out its length, the general appearance of which may be 




Fig. 19.— Linen. 

compared to a stick of bamboo. The central canal of the 
fibre is extremely narrow, running like a small thread 
through the length of the fibre. The cell walls are further 
marked by numerous pores, which appear as small dark 
lines running from side to side, but not meeting in the 
centre. 



COTTON AND LINEN FIBEES 71 

In the treatment necessary for making paper these 
characteristics are largely destroyed, and while it is quite 
easy to ascertain that a paper is of linen, or of cotton, or 
that a paper is mainly cotton with a small percentage of 
linen, yet there are conditions under which it is difficult to 
determine the exact percentage of cotton or linen in a rag 
paper. If, for example, a paper contains nearly equal 
quantities of cotton and linen, the exact proportions can- 
not'be determined closer than 10 per cent., especially in 
well-beaten papers. 

Reagent foe Staining Fibres. 

Preparation. — Dissolve 2*1 grams potassium iodide and 
O'l grams iodine in 5 c.c. of water. Mix this solution with 
a solution containing 20 grams of dry zinc chloride in 
10 c.c. of water. Allow the mixture to stand ; pour off the 
clear liquid into suitable bottles. 

Coloration Producbd. 

Cotton, linen, hemp. — Wine red. 
Esparto, straw and wood cellulose. — Bluish violet. 
Mechanical wood, unbleached jute. — Yellow. 
Manila hemp. — Blue, bluish grey to yellow. 



CHAPTEE IV 

espakto and straw 

Esparto Papers. 

The value of Esparto for the manufacture of high-class 
printing and medium quality writing paper is well known. 
This material has qualities which cannot readily be 
obtained from other fibres, such as rag and wood pulp. 
It is chiefly used in papers required for lithographic 
printing, books, and art illustration, since it gives a sheet 
having a good surface and one which is soft and flexible. 

The grass is obtained from Spain, Morocco, Algeria, 
Tunis, and Tripoli, in which countries it grows wild, 
requiring very little cultivation. The condition of the 
crop is improved by proper treatment, and in districts 
where the grass is cut for export as a paper-making 
material attention is given to cultivation. 

The plant grows to a height of three or four feet, and 
when mature the long blades of grass curl up into the form 
of a cylinder resembling a piece of wire. The leaf consists of 
two parts, the stalk and a sheath, which are easily separated 
when harvested. The grass is pulled up by hand and stacked 
into heaps in order that it may be dried by the heat of the 
sun, after which process it is carefully picked over for the 
removal of all extraneous matter and impurities. It is then 
graded, the best sorts being kept for weaving, and the 
remainder being sold for paper-making. It is packed up 
into large bales of about 4 cwt. capacity, compressed into 
small bulk by powerful presses, and shipped to England. 



ESPARTO AND STEA.W 



73 



Esparto Pulp. — The first process in the manufacture of 
the paper is cleaning. The bundles of grass are opened 
up, shaken out, and put through a willowing machine. This 
consists of a hollow conical drum, the outer surface of which 
is a coarse wire cloth. Inside the drum is fitted a shaft 
provided with wooden teeth, and as the grass passes through 
it is tossed about and the dust removed. The clean grass 
is conveyed by travelling belts to the digester house. For 
the*production of a high-class paper the grass is often 
examined by girls, who stand on either side of the 
travelling conveyer and take out any coarse root ends and 
foreign material not removed by the willowing machine. 

Boiling. — The object of submitting esparto to chemical 
treatment is to obtain a pure paper-making fibre known as 
cellulose. The composition of this raw material is shown 
by the following analysis : — 



Spanish Esparto. 




Cellulose .... 


. 48-25 


Water 


9-38 


Aqueous extract 


. 10-19 


Pectous matter 


. 26-39 


Fatty matter .... 


2-07 


Ash 


3-72 



100-0 



Yield of dry cellulose obtained in 
actual practice from good raw 
material 



45 to 48 t 



By boiling the esparto with caustic soda under pressure 
for a stated time, the non -fibrous constituents are removed, 
leaving the cellulose in a more or less pure form according 
to the severity of the chemical treatment. 



74 



THE MANUFACTURE OF PAPER 



In practice the grass is packed tightly into upright 
stationary digesters and a definite quantity of caustic 
soda solution added, the amount of chemical used being 
equal to 15 — 18 per cent, of the weight of grass packed 
into the digester. The form of digester almost universally 
employed is that known as the Sinclair's " vomiting " boiler, 
which is constructed so that a continuous circulation of the 




Fig. 20. — An Esparto Duster. 

liquid is maintained by means of what are called " vomit " 
pipes. These are fitted to the sides of the digester in such 
a manner that the caustic soda solution circulates from the 
bottom of the digester, up through the "vomit" pipes, 
and is discharged downwards upon the contents of the 
boiler through a perforated plate fixed in the upper part 
of the digester. The requisite quantity of caustic soda 
solution is placed in the digester, and steam admitted into 



ESPAETO AND fSTRAW 



75 



the bottom of the vessel while the grass is being thrown in. 
In this way a much larger weight of grass can be boiled at 




Fig. 21. — Sinclair's " Vomiting " Esparto Boiler. 

one operation, since the bulk is greatly reduced when the 
grass has become thoroughly soft and wet. 

When the boiler is loaded the inlet is closed up and steam 



76 



THE MANUFACTURE OF PAPER 



turned on to the full pressure of about 40 or 50 lbs., this 
being maintained for a period of about four hours. The non- 
fibrous constituents of the esparto are gradually dissolved 
out by the caustic soda, and when the operation is com- 
pleted the black liquor is run off from the digester into 
large store tanks, and the esparto grass which remains in 




iiiiiiiimuiiniiii.itiijijiiiiiiiH \>inii,ii,„. 



e V 



hl/"iiii i>ii unlit \ t>iiiiiiii,in>m>i,iij}}n i injj)nR} iii Mi.iiiiiiiii, 



f i 



^ 



ll/i/numi/irT;^ uiiii/,,i/n.ii,i/ii„ w7\ rmTr. 



9 9 

Fig. 22.— a Porion Evaporator. 



7nm^ """-y ^'- -'^Y' t."^ 



the digester is then completely washed until the soda is 
almost entirely washed out. 

The conditions for boiling and bleaching esparto are 
varied by the paper-maker as circumstances require. A 
maximum yield of fibre is obtained when the least possible 
quantity of caustic soda is used, but a larger percentage of 
bleaching powder may be necessary to ensure a well 
bleached pulp. The use of an excess of caustic soda is 



ESPAETO AND STEAW 



77 



probably the general practice for several reasons, amongst 
which may be noted the advisability of guarding against 
irregularities in the quality of the esparto, and consequent 
insufficient boiling, as well as the advantage of having some 
free caustic in the spent liquors to prevent the furring up 
of the tubes of the evaporating apparatus in the soda 
recovery department. 

The following experiments, given by a contributor to the 
Paper Trade Review some years ago, are interesting as 
showing the effect of varying proportions of caustic soda 
used per unit of grass : — 

EXPEEIMENTS RE YiELD OP AlR-DRY BLEACHED PULP PKOM ObAN 

Esparto. 
Air-dry Pulp containing 10 per cent, water. 



No. of 
Experi- 
ment. 


Esparto. 


Soda Liquor. 


Conditions of Boiling. 


Weight 

of 

Air-dry 

Pulp. 

Grams. 


Dry 
Pulp 
on Dry 
Esparto. 
Per 
cent. 


Bleach- 


Wt. 
t.aken. 
Grams. 


Volume, 
C.C. 


Per 

cent. 
NaaO. 


Time. 
Hours. 


Temp. 

°C. 


Pres- 
sure. 
Lbs. 


Powder 
Per 

cent. 


1 
2 
3 


200 
200 
200 


800 
800 

800 


1-58 
2-13 
2-69 


3 
3 
3 


142 
142 
142 


55 
55 
55 


87-30 
80-67 
72-00 


43-65 
40-33 
36-00 


29-5 
18-5 
10-5 



Practical Data calculated erom Experiments. 



No. of 
Experi- 
ment. 


Boiling. 


Weight of 
Esparto to 
give 1 ton 

Pulp. 

Cwts. 


60 per cent. 

Caustic Soda 

required to 

Dige.st 

Esparto. 

Cwts. 


Bleaching 

Powder 

required to 

Bleach 1 ton 

Air-dry Pulp. 

Cwts. 


For One Ton of 
Esparto used. 


Time. 
Hours. 


Pres- 
sure. 
Lbs. 


60 per 

cent. 

Caustic. 

Lbs. 


Bleach- 
ing 
Powder. 
Lbs. 


1 
2 
3 


3 
3 
3 


55 
55 
55 


45-8 
49-5 
55-5 


4-30 
6-27 
8-90 


5-26 
3-39 
1-96 


210 
282 
358 


260 

156 

79 



78 THE MANTJFACTUEE OP PAPER 

Recovery of Spent Liquor. — As it is possible to recover 
75 to 80 per cent, of the soda originally used in digesting 
the esparto, the washing of the boiled grass is conducted on 
scientific principles in order to ensure a maximum recovery 
of soda at a minimum cost. 

The recovery is effected by evaporating down the black 
liquor, together with the washing waters, to a thick 
syrupy mass, which can be burnt. The organic and 
resinous constituents of the esparto which have been 
dissolved out by the caustic soda, forming the soluble 
soda compounds, ignite readily, and during combustion 
the organic soda compounds are converted more or less 
completely into crude carbonate of soda. 

It is obvious, then, that the cost of recovery depends mainly 
on the quantity of weak washing water which has to be 
evaporated. Consequently methods are devised by means 
of which the grass is thoroughly washed with as little 
water as possible, and some of the methods are very 
ingenious. 

The spent liquors and washing waters are evaporated to 
a small bulk in a vacuum multiple effect apparatus, and 
the thick liquid mass obtained by evaporation is burnt 
either in a rotary furnace or on an ordinary hearth. Every 
precaution is taken to effect this operation with a minimum 
quantity of coal. The burning off of this mass results in 
the formation of a black substance which is taken away 
from the furnace and allowed to char or slowly burn until 
the impure white soda ash, or carbonate of soda, is 
obtained. 

Two systems of recovery are in general use, which 
deserve a brief notice : — 

Direct Evaporation. — The liquors may be evaporated to 
a small bulk ready for incineration by treatment in long 
shallow pans or furnaces, the heat necessary for the process 



ESPAETO AND STEAW 



79 




W 



I 



80 THE MANUFAOTUEE OF PAPEE 

being obtained mainly from the combustion of the thick 
concentrated liquor. The most familiar type of this form 
of apparatus is the Porion evaporator. 

The combustion of the concentrated liquor is started by 
a coal furnace at one end of the apparatus. The thick 
viscous mass catches fire and burns with a fierce flame, and 
the heat is utilised in evaporating the weaker liquors which 
flow continuously through shallow brick troughs, the surface 
of which is freely exposed to the heat and flames from the 
hearth where the organic soda compounds produced in the 
boiling of esparto are being incinerated and converted into 
soda ash. 

Under suitable conditions this evaporator is most 
economical in its results. It can be erected cheaply, and 
when all the heat is fully used in every possible direction 
it can be worked at a low cost compared with the more 
modern multiple effect evaporators. 

Vacuum Multiple Effect Evaporation. — Advantage is taken 
of the fact that water boils at a lower temperature in a 
vacuum than at the ordinary pressure of the atmosphere. 
There are many forms of apparatus based on this principle, 
amongst which the most recent is Scott's evaporator. The 
black liquor from the boilers is pumped through tubes heated 
externally by high-pressure steam. The liquor is passed 
into a chamber in which a slight vacuum is maintained, so 
that immediately on entering, the liquor parts with a good 
deal of water in the shape of steam. The steam liberated 
is utilised in producing further evaporation of the partially 
concentrated liquor, and this operation is repeated several 
times until the concentration is effected to the desired 
point. 

In most cases the actual incineration of the thick liquor 
is carried out in a rotary furnace when such an apparatus 
as this is used. 



ESPAETO AND STEAW 



81 



Evaporation Table. 

Showing the volume of liquor obtained by evaporating 1,000 gallons 
of weak black lye of density d to a higher density D. 



Lower 
Density d 


Higher Density D (Twaddell) at 100° F. 




















(at 100° F.). 


20. 


25. 


30. 


35. 


40. 


45. 


50. 


55. 


60. 


2» 


100 


80 


66-6 


57-1 


50 


44-4 


40 


36-3 


33-3 


3 


150 


120 


100 


85-7 


75 


66-6 


60 


54-5 


50 


4 


200 


160 


133-3 


114-3 


100 


88-8 


80 


72-7 


66-6 


5 


250 


200 


166-6 


143 


125 


111-0 


100 


90-9 


83-3 


6 


300 


240 


200 


171-4 


150 


133-3 


120 


109 


100 


7 


350 


280 


233-3 


200 


175 


155-5 


140 


127 


116-6 


8 


400 


320 


266-6 


228-6 


200 


177-6 


160 


145-5 


133-3 


9 


450 


360 


300 


257 


225 


200 


180 


163-5 


150 


10 


500 


400 


333-3 


286 


250 


222 


200 


181-8 


166-6 



Example -. — 1,000 gallons of weak liquor at a density of 7° Twaddell 
are reduced to a volume of 200 gallons having a density of 35° 
Twaddell, or to a volume of 140 gallons with a density of 50° 
Twaddell, by evaporation. 

Preparation of Caustic Soda. — The crude soda ash 
recovered from previous boiling operations is dissolved in 
large lixiviating tanks and extracted with hot water. The 
clear solution obtained after all impurities have been allowed 
to settle is pumped up into the causticising tanks, where 
it is converted into caustic soda, the loss due to the amount 
of soda not recovered being made up by the addition of 
ordinary soda ash. The causticising pans are large circular 
iron vessels usually 9 feet diameter and 8 or 9 feet deep, 
into which a known volume of the recovered carbonate 
of soda solution is placed. 

A weighed quantity of ordinary quicklime is then put 
into a perforated iron cage which is fixed inside the 
causticising pan at such a level that the whole of the 
lime is immersed in the solution. The liquor is kept in 



82 THE MANUFACTUEE OF PAPEE 

constant circulation by means of an agitator and heated to 
boiling point, with the result that the chemical reaction 
sets in, the carbonate of soda being converted into caustic 
soda and the lime being thrown out as chalk. When the 
operation is completed, the steam is turned off and the 
chalk allowed to settle. The clear liquor is carefully 
strained off and pumped up into store tanks from which the 
required quantities are drawn off into the digesters as 
circumstances demand. 

Washing. — The grass which has been partially washed in 
the digester is dug out by the workmen and discharged 
through a manhole fitted on one side of the digester near 
the bottom. It is then conveyed in any convenient manner 
to the breaking engine, in which the grass is more com- 
pletely washed. This important machine has already been 
described on page 53. The floor of the vessel slopes slightly 
upward towards the front of the roll and falls suddenly 
behind the roll, in order to promote a circulation of the 
contents of the engine round and round the vessel. 

A definite weight of boiled grass is thrown into the engine 
together with a large quantity of fresh water. The circu- 
lation of the roll draws the mixture of pulp and water 
between the knives, breaking it up and at the same time 
discharging it behind the beater roll, and producing a 
continuous circulation of the mixture in the two sections of 
the vessels. 

The dirty water is continuously removed from the vessel 
by means of a " drum- washer." This is a large hollow 
drum, the outer surface of which consists of a fine wire 
cloth, the interior of the washer being fitted with specially 
curved scoops. The drum- washer is lowered until it is half 
immersed in the mixture of pulp and water, and as it rotates 
the dirty water finds its way through the wire cloth, being 
caught up by the internal scoops and discharged through a 



ESPAETO AND STRAW 83 

pipe to a drain outside the breaking engine. At the same 
time fresh water is run into the vessel at one end, and the 
continuous washing of the pulp thus effected. 

Bleaching. — The clean boiled grass is bleached by means 
of a solution of chloride of lime. 

There are several methods used for this purpose, each of 
which has special advantages of its own, though this is 
largely a question of local conditions : — 

(A) The pulp can be bleached in the washing engine 
directly the grass has been sufficiently cleaned. In this 
case the flow of fresh water is stopped and as much water 
as possible removed by means of the drum-washer. The 
drum-washer is then raised out of the pulp and a known 
volume of bleaching powder solution corresponding to a 
definite weight of dry powder is added to the contents of 
the breaking engine. The amount used depends on the 
quantity of dry grass in the breaking engine, the usual 
proportion being 8 to 10 per cent, on the calculated air- 
dry weight of raw grass. As the stuff circulates round 
the engine the colour gradually changes from dark yellow 
to white. 

The process is sometimes hastened by blowing a small 
quantity of steam into the mixture and thereby raising its 
temperature. Considerable care must be exercised in using 
heat, because pulp bleached quickly by this means is liable 
to lose colour at the later stages of manufacture. 

When the pulp has been bleached to the required extent, 
the drum-washer is again lowered into contact with the 
bleached pulp, and the latter is thoroughly washed so as to be 
quite free from traces of bleach and other soluble impurities. 

(B) Esparto is often bleached in a " Tower " bleaching 
engine which consists of a tall cylindrical vessel of 9 feet 
diameter, and 15 or 16 feet deep, at the bottom of which is 
fixed a small centrifugal pump. 

G 2 



84 THE MANUFACTUEE OF PAPER 

The boiled grass together with sufficient water and clear 
bleaching powder solution is placed in the engine ; the 
centrifugal pump draws the mixture from the bottom of the 
vessel and discharges it, by means of a large external pipe, 
direct into the top of the vessel, where, as it falls, it comes 
into contact with a circular baffle-plate, which distributes 
the pulp evenly over the surface of the mixture in the 
vessel. A continuous and rapid circulation is thus main- 
tained, and the process is skid to be very effective. The 
bleached pulp is subsequently washed free from any traces 
of bleach. 

(C) Esparto is frequently bleached by the "steeping" 
process. In this case the pulp is washed in the breaking 
engine, mixed with the required quantity of bleach, and at 
once discharged through the outlet pipes of the engine into 
large brick tanks, where the bleach is allowed to act quietly 
upon the boiled grass. This method produces a pulp of good 
colour and is economical. 

Whichever process of bleaching is adopted, it is necessary 
to remove all the by-products formed during the process, 
as these soluble by-products if left in the mixture produce 
a lowering of colour. 

The presence of small traces of bleaching powder solution 
can be detected by the use of starch and potassium iodide 
test papers. If a handful of the pulp after bleaching, when 
squeezed out, does not turn the test paper violet or blue, 
then the absence of any free bleach is taken for granted. 
The slightest trace of bleach will turn such test papers blue 
or violet according to the amount present. This is the tes 
usually applied by the men in charge of the bleaching 
operations. 

Making Sheets of Esparto Pulp. — For convenience in 
handling, it is usual to work up the washed and bleached 
pulp into the form of moist sheets. This is effected on a 



ESPAETO AND STEAW 



85 




p4 

OQ 



86 THE MANUFACTURE OF PAPEE 

machine known as a " presse-pate," an apparatus which 
closely resembles the wet end of a paper machine. It con- 
sists of a set of flat strainers or screens, a horizontal wire 
similar to the paper machine wire, provided with deckles, 
the usual couch rolls, and press rolls. 

The pulp diluted with water is passed through the screens 
and on to the horizontal wire, where it is formed into a 
moist sheet, the water draining away from the wire, and 
also being removed by vacuum pumps. The thick sheet of 
pulp is carried through the couch rolls and press rolls, being 
finally wound up on a wooden roller at the end of the 
machine. In this moist condition it is ready for use in the 
mill. 

Dry Esparto Pulp. — When the bleached pulp is intended 
for export a more elaborate machine is used — to all intents 
and purposes a paper-making machine — by means of which 
the continuous sheet of moist pulp is dried and cut up into 
smaller sheets of suitable size. These dried sheets are 
packed up in bales containing 2 cwt. or 4 cwt. of dried 
pulp, then wrapped in hessian and bound with iron wires. 

Other Methods. — Since the yield of esparto pulp from the 
raw material is less than 50 per cent, and it requires 
45 cwt. of grass to make one ton of finished pulp, methods 
have been devised for treating the grass in the green state 
in the districts where it is grown, but so far nothing has 
been done on a large scale. 

The isolation of the cellulose by alkaline treatment in the 
cold has been suggested, but the method never passed 
beyond the experimental stage. This process was indeed 
first mentioned by Trabut, who many years ago considered 
that the removal of non-fibrous constituents from fresh 
grass could be readily accomplished by the less drastic 
treatment of the esparto with alkaline carbonates of soda 
and potash at ordinary temperatures. 



ESPAETO AND STEAW 87 

The production of esparto pulp hy bacteriological fermenta- 
tion is an idea of later date. According to the inventor, 
the grass is crushed mechanically by means of rollers and 
then immersed in sea water inoculated with special bacillus 
obtained from esparto, and gradually resolved into cellulose 
and soluble by-products by fermentation which is complete 
in about eleven days. The commercial value of this idea 
has not yet been demonstrated. 

Esparto Pulp : Microscopical Features. 

The pulp of esparto when examined under the microscope 
is easily recognised, first by the characteristic appearance 
of the long slender cylindrical- shaped fibres, and secondly 
by the numerous cells always present. These cells consist 
of cuticular vessels with serrated edges, and also of small 
pear-shaped seed hairs, the shape of which is a ready means 
of identifying esparto. An examination of the transverse 
section of the raw material indicates the source of these 
pear-shaped vessels. 

Test for Esparto in Papers. — Paper containing esparto 
fibre may be tested by means of a weak solution of aniline 
sulphate. The suspected paper is gently heated in the test 
reagent, and if esparto is present the paper turns a rose-red 
or pink colour, the depth of colour being a measure of the 
amount of esparto. Most of the modern book papers are 
prepared from chemical wood pulp and esparto mixed in 
varying proportions, and while this test can be used as a 
means of detecting a small or a large proportion of esparto, 
a microscopical examination is required for a more accurate 
estimation. 

The proportions used by the paper-maker depend upon 
the weighing out of the wood pulp and esparto more or less 
accurately, while the microscopical test is based upon the 
relative proportions as represented by the volume of fibres 



88 



THE MANUFACTUEE OF PAPER 



of each class on the glass slip placed under the microscope. 
Since the wood pulp consists of a number of broad flat 
ribbon-like fibres, and the esparto of small cylindrical fibres, 




Fig. 25. — Esparto Pulp. 

considerable practice is necessary in making a proper 
analysis of the two constituents in paper. 

Straw. 

The use of straw for the manufacture of paper was first 
brought prominently into notice about the year 1800 by 



STEAW 



89 



Matthias Koops, who published a book printed on paper 
made from straw, but it was not until 1860 that this 
material was used in any large quantity. 

Straw is now converted into a bleached paper pulp for 




Pig. 26. — A Cj'lindrical Digester for Boiling Fibre. 

news and printings, and is also utilised for the manufacture 
of straw boards. 

The production of a white paper pulp from straw is 
carried out in a manner similar to that used in the case of 
esparto fibre, viz., by digestion with caustic soda under 
pressure and subsequent bleaching. As the straw contains 
considerable quantities of siliceous matter, the chemical 
treatment necessary to reduce the material to paper pulp is 
more severe, a stronger solution of caustic soda being used, 



90 THE MANUFACTURE OF PAPER 

and the process of digestion being carried out at a higher 
temperature. 

For the best quality of straw cellulose, the material is 
cut up into small pieces by machines which resemble an 
ordinary chaff-cutter, and the knots taken out by a 
separating machine. In most cases, however, the whole 
straw is simply cut up into small lengths of about one to 
two inches long, and placed at once in the digester. When 
the straw is contaminated with foreign weeds, sand, husks, 
and similar substances, as is usually the case, it is care- 
fully hand-picked by girls, who remove these impurities, 
which tend to produce particles of unbleached matter in the 
finished pulp. The expense of this preliminary cleaning 
process is more than compensated for by the enhanced value 
of the bleached straw pulp. 

Digesting. — The cut straw is boiled in rotary cylindrical 
or spherical vessels, stationary upright boilers of the vomit- 
ing type being seldom employed because the circulation of 
the caustic soda liquor does not take place freely with straw 
packed in the latter. 

As the material is very bulky, some of the liquor is first 
put into the boiler and the steam admitted while the straw 
is being thrown in. By this means the straw is softened 
and reduced in bulk, so that a larger quantity can be added 
before the digester is quite full. The full amount of caustic 
soda is then made up by further additions of liquor, and 
the contents of the digester heated by high-pressure steam 
for four to six hours. 

The conditions of treatment are shown by the following 
trial : — ■ 

Amount of straw . . . 5,600 lbs. 

Caustic soda, 20 per cent. . . 1,120 lbs. 

The caustic soda was added in the form of a liquor, 



STEAW 91 

having a volume of 2,012 gallons and a specific gravity 
of 1-055. 

Time of boiling .... 5 hours. 
Pressure 60 lbs. 

Washing. — The boiled straw is discharged into large 
tanks placed below the digester and washed with hot water, 
the smallest possible quantity being used consistent with 
complete washing in order to prevent the accumulation of 
large volumes of weak lye. The spent liquor and washing 
waters are drained off into store tanks and evaporated in a 
multiple effect apparatus by the same process as that used 
for esparto pulp. The last washings are usually run away 
because the percentage of soda in them is too small to pay 
for the cost of recovery. 

The final washing of the straw pulp is completed by the 
use of a breaking engine or potcher. As straw pulp con- 
tains a large proportion of cellular matter which cannot be 
regarded as true fibres, there is always a danger of con- 
siderable loss in yield if the use of the breaking engine is 
extensively adopted, because the short cells escape through 
the meshes of the drum-washer. The washing is most 
economically effected in the tanks if a good yield of pulp is 
required. 

Separating out Knots. — The broken pulp from the break- 
ing engines is diluted with large quantities of water and 
pumped over sand traps in order to remove knots and 
weeds which have resisted the action of the caustic soda. 
These traps consist of long shallow trays, perhaps sixty to 
eighty yards long, one yard wide, and nine inches deep, 
containing boards which stretch from side to side, sloping 
at an angle, and nailed to the bottom of the trays. The 
dilute pulp flows through the trays, leaving the heavy 
particles, knots, and foreign matter behind the sloping 



92 THE MANtTFACTUEE OF PAPER 

boards, and finally passes over the strainers, which retain 
any large coarse pieces still remaining. 

Making Sheets of Pulp. — The mixture from the strainers 
contains a large excess of water which has to be removed 
before the pulp can be bleached. For this purpose a wet 
press machine (see page 103) or a presse-pate (see page 85) 
is employed, and the wet sheets of pulp are then ready for 
bleaching. 

Bleaching. — The process by which the pulp is bleached is 
exactly similar to that used for treating esparto. 

From 1870 to 1890 large quantities of straw were used 
for the manufacture of newspaper in conjunction with 
esparto and wood pulp, but the price of the material 
was gradually advanced so that it could not be used with 
advantage, especially as the production of wood pulp gave a 
material which was much cheaper, and which could be 
utilised at once without chemical treatment. 

In the manufacture of newspaper the tendency during 
recent years has been to make the paper mill operations as 
mechanical as possible and to dispense with the preliminary 
operations which are essential for the manufacture of half- 
stuff, the chemical processes being left in the hands of the 
pulp manufacturers. 

The manufacture of straw cellulose is now practically 
confined to Germany, but small quantities of the bleached 
straw cellulose are imported because the pulp imparts 
certain qualities to paper which improve it, notably in 
making cheap printing papers harder and more opaque. 

Microscopical Features of Straw. 

The paper pulp obtained from straw consists of a mixture 
of short fibres together with a large proportion of oval- 
shaped cells. The fibres are short and somewhat resemble 
esparto, but the presence of the smaller cells is a sure 



MICEOSCOPIOAL FEATUEES OF STRAW 



93 



indication of the straw pulp. The fibres themselves closely 
resemble the fibres of esparto, but as a rule the latter 
are long slender fibres, while the straw fibre is very often 
bent and twisted or slightly kinked. 




Fig. 27. — Straw. 

The only method of distinguishing between straw and 
esparto is by examination with the microscope. There is no 
chemical reagent known which will produce a colour reaction 
on a paper containing straw that will serve to distinguish it 
j[rom a paper containing esparto. If such papers are gently 



94 THE MANUFACTUEE OF PAPER 

heated in a weak solution of aniline sulphate a pink colour 
is slowly developed, the intensity of which is to some 
extent a measure of the amount of straw or esparto 
present. 

Straw and esparto are usually described in text-books 
under one heading, partly because the fibres possess strong 
resemblances in physical and chemical constitution, and 
partly because the methods of manufacture are identical. 
At the same time the qualities of the two pulps are so 
different that they cannot be used indiscriminately, the 
one for the other. Straw cellulose cannot be utilised in 
the place of esparto, particularly for light bulky papers. 
Hence in magazine and book papers containing a fibre which 
gives a pink coloration with aniline sulphate it is fairly 
safe to assume that esparto pulp is present. 



CHAPTEE V 

wood pulp and wood pulp papbes 

^ The Manufacture of Mechanical Wood Pulp. 

Wood is converted into pulp suitable for the manufacture 
of paper by methods which produce two distinct varieties. 
The first is mechanical ivoocl pulj), so called because it is 
made by a purely mechanical process. The second is termed 
chemical ivood pul-p from the fact that the material is sub- 
mitted to chemical treatment. 

Ground Wood and Celhdose. — The two varieties of pulp are 
sometimes distinguished by the use of the terms ground wood 
and cellulose. In the former case the description implies a 
product consisting of pulp obtained by grinding wood into 
a fibrous condition, while in the second the word suggests 
a purified chemical product freed from the resinous and 
non-fibrous constituents found in wood. This is, in fact, the 
essential difference, for mechanical wood pulp consists of 
fibres which have been torn away from wood by means of a 
grindstone ; it differs but slightly in chemical composition 
from the original raw material and contains most of the 
complex substances natural to wood. Chemical wood pulp, 
on the other hand, consists of fibre isolated from wood in 
such a manner that the complex non-fibrous substances are 
more or less entirely removed. The difference between 
these two pulps is shown in the following approximate 
analysis of spruce wood, and of the pulp derived from it. 
The composition of the mechanical pulp is practically 
identical with that of the wood itself. 



96 



THE MANUFACTUEE OF PAPER 



Composition of Spruce Wood, and of Chemical Wood 
Pulp (Spruce). 





Wood 


Chemical 




(Spruce). 


Wood Pulp. 


Cellulose 


530 


88-0 


Eesin .... 


1-5 


0-5 


Aqueous Extract . 


2-5 


0-5 


Water .... 


120 


8-0 


Lignin .... 


30-5 


2-5 


Ash ... . 


Oo 


0-5 




100-0 


100-0 



The use of mechanical wood pulp is generally confined to 
the manufacture of news, common printings and packing- 
papers, cardboards, and boxboards. It possesses very little 
strength, quickly discolours when exposed to light and air, 
and gradually loses its fibrous character. The chemical 
wood pulp is a strong fibre, from which high-class papers 
can be manufactured, the colour and strength of which 
leave little to be desired. 

Species of Wood. — The woods most commonly used for the 
manufacture of wood pulp belong to the order Coniferae, or 
cone-bearing trees. In Europe the spruce and silver fir 
are the chief species, while in America spruce, balsam, 
pine, and fir are employed. The harder woods, such as 
hemlock, beech, larch and others, are not converted into 
pulp by the mechanical process. 

Timber Operations. — The trees are cut down in the early 
part of winter by gangs of men specially trained to the work. 
The organisation of a lumber camp when the operations are 
of an extensive character is very complete and carefully 
arranged, every detail being attended to in order to get out 
the wood as cheaply and expeditiously as possible. The 



WOOD PULP AND WOOD PULP PAPEES 97 

branches and small tops are removed from the trees when 
they are fallen, and the trunks cut into logs of 12, 14, or 
16 feet in length, and afterwards piled up on the banks of 
the nearest river, or on the ice, ready for the breaking up 
of the winter. 

As soon as the ice breaks up and the rivers become 
navigable the logs are floated down to their destination, 
in some cases hundreds of miles from the scene of 
operations. Where rivers are not available the timber is 
brought out by horses or bullocks, or by means of a light 
railway. 

Log Cutting. — ^As the timber arrives at the mill it is 
carefully measured, both as to its diameter and length, in 
order that a record may be kept of the quantity used. 
Some of the logs are piled up in the storeyard for use in 
the winter, and the remainder converted into pulp day by 
day. The logs are first cut into short pieces about 2 feet 
long by means of a powerful circular saw, the arrangements 
for this work being devised so as to keep down the cost of 
labour as much as possible. All waste pieces are thrown 
aside to be utilised as fuel. 

Barking. — The bark on the logs is removed in one or two 
ways. Much of it is knocked off during the transfer from 
the forest to the mill, but even then the wood requires to 
be cleaned. In Norway and Sweden the wood is treated in 
a tumbler or a barker, while in America and Canada the use 
of the tumbler is practically unknown. 

The barker consists of a heavy iron disc fitted with 
knives, usually three in number, which project from the 
surface of the disc about half or three-quarters of an inch. 
The barker rotates in a vertical position, and the short 
pieces of wood are brought one by one into contact with the 
disc in such a manner that the bark is shaved off by the 
knives. The machine is provided with conveniences for 

P. H 



98 



THE MANUFACTUEE OF PAPEE 



pressing the wood against the disc and for turning the logs 
as they are barked. 

The machine is encased in a strong cast-iron cover, and 
all the bark shaved off is carried away by the strong current 




Fig. 28. — A Pair of Barkers for removing Bark from Logs 
of Wood. 

of air set up by the rapid motion of the disc, and 
subsequently burnt. 

The tumbler system is quite different. In this case the 
short pieces are thrown into a large circular drum with hot 
water, and the bark taken off by the friction of the pieces 
as the drum rotates. The loss of material is of course less 



WOOD PULP AND WOOD PULP PAPEES 



99 



in this process, but the wood is not cleaned quite so 
effectively. 

The wood at this stage can be used either for the manu- 




FiG. 29. — View of Horizontal Grinder (a), witli Section (b). 

facture of mechanical or chemical pulp. As a general rule 
the pieces are taken indiscriminately for either process, but 
sometimes the wood is sorted out, the clean stuff free from 
knots and blemishes being reserved for high quality chemical 
pulp. 

H 2 



100 THE MANUPACTUEE OE PAPEE 

Grinding. — The main feature of the grinding process is 
the attrition of the wood when held against the surface of a 
rapidly revolving grindstone, the fibres as they are rubbed 
off being instantly carried away from the stone by a current 
of water. A complete description of the machines used and 
the modifications of the process practised by manufacturers 
is impossible in this book, but the following points will be 
sufficient. 

The machine consists of a large grindstone about 
54 inches in diameter, and 27 inches thick. It rotates 
in a vertical or in a horizontal position at a high speed. 
The stone revolves inside a casing which is provided 
with a number of pockets, so called, into which the pieces of 
wood are thrown at regular intervals, as fast as the wood is 
ground by the friction of the stone. 

A continual stream of water playing upon the surface of 
the stone washes, away the pulp into a tank or pit below the 
machine. 

The quality of the pulp may be varied by the conditions 
under which it is made. By limiting the proportion of 
water so that the wood remains in contact with the stone 
for a longer time the temperature of the mass in the pockets 
rises. Such liot ground jjidp, as it is termed, is tough and 
strong. 

When the fibres are washed away from the stone as fast 
as they are produced the temperature does not rise, and cold 
ground pulp is made, which is not characterised by the 
somewhat leathery feel of the pulp made at the higher 
temperature. 

The surface of the stone plays an important part also. If 
the stone is smooth the wood is rubbed away slowly, but if 
the surface has been roughened and grooved by means of a 
special tool the fibres are torn away quickly. In the first 
case the pulp comes from the stone in a finely-ground slate 



WOOD PULP AND WOOD PULP PAPERS 



101 



and in a uniform condition, while in the second the pulp is 
coarse and chippy. 

The output of the machine is, however, much increased 
by the use of sharp stones and by the application of con- 
siderable pressure to the blocks of wood. 




Pig. 30. — A Vertical Grinder for making Hot Ground Mechanical 
Wood Pulp. 

Screening. — The mixture of water and pulp leaving the 
grinder falls into a tank below the stone, all large chips 
being retained by means of a perforated plate. The finer 
pulp, still too coarse for use, is then pumped to the screens, 
which serve to remove all chippy and coarse fibres and 



102 THE MANUFACTUEE OF PAPEE 

produce a uniform material. The shaking sieve consists 
of a shallow tray, the bottom of which is a brass plate or 
series of plates perforated with small holes or slits. The 
pulp flows on to the tray, which is kept in a state of violent 
agitation, the fine pulp passing through the holes and the 
coarser pieces working down to the lower edge of the tray 



Fig. 31.— Centrifugal Screen for Wood Pulp. 

into a trough which carries them away. The fiat screen 
is somewhat different in construction, but the principle of 
separation is the same. It consists of brass perforated 
plates forming the bottom of a shallow cast-iron tray, 
continually agitated by means of cams fixed to the under 
surface of the trays. 

The centrifugal screen is a cage made of finely perforated 



WOOD PULP AND WOOD PULP PAPERS 



103 



brass sheeting which revolves at a very high rate of speed 
inside a circular cast-iron vessel. The pulp flows into the 
interior of the cage, the fine fibres being forced through 
the screen by the centrifugal action of the machine, and the 
coarse material is retained. 

Wet Pressing. — The pulp leaving the screens is mixed 
with such a large quantity of water that it is necessary 



-i 



— L . 




;ms^<\^K\\^^\\\\\m.mii^ 



Pig. 32. — Section of Centrifugal Screen for Wood Pulp. 

to concentrate it. This is effected by means of the wet 
press machine (Fig. 41). The pulp and water are pumped 
into a wooden box in which revolves a large hollow 
drum, the surface of this drum consisting of a fine wire 
cloth of about 60 or 70 mesh. The drum is not entirely 
immersed in the mixture, so that as it rotates the pulp 
forms a skin or thin sheet on the surface, and the water 
passes away through the wire into the interior of the 



104 THE MANUFACTUEE OF PAPEE 

hollow drum. The drum carries the thin sheet out of the 
box and above the level of the mixture until it comes into 
contact with an endless blanket or felt, which is pressed 
against that part of the drum not immersed in the liquid. 

By this means the thin sheet is transferred to the felt 
and carried between squeezing rolls to the finishing rolls. 
The felt, carrying on its upper surface the thin sheet of pulp, 
passes between two rolls, usually 16 to 20 inches in 
diameter, the upper being made of wood and the lower 
one of cast iron. The pulp adheres to the upper drum and 
the felt passes round the lower drum back to the box con- 
taining the mixture of pulp and water ; the thin sheet is 
continuously wound on the upper roll until a certain 
thickness is reached. 

When this occurs the attendant removes the tbick sheet 
by a dexterous movement of a sharp stick across the face 
of the roll. The wet pulp at this stage consists of 30 per 
cent, air-dry pulp and 70 per cent, of water. 

Hydraulic Pressing. — The sheets taken from the wet 
press machine are folded into a convenient shape and piled 
up, coarse pieces of sacking being placed between the sheets. 
At stated intervals the piles are submitted to pressure in 
hydraulic presses in order to remove further quantities of 
water, which slowly drains away through the sacking. In 
this way a mass of pulp in the form of thick folded sheets 
containing 50 per c^nt. of dry wood pulp is produced. 

The pieces of sacking are taken out and the sheets put 
up in bales of any required weight, usually 2 cwfc. or 4 cwt. 

The Manufacture of Chemical Wood Pulp. 

Most vegetable fibres are converted into pulp by alkaline 
processes, that is by digesting the raw material with caustic 
soda and similar alkaline substances. Wood may be treated 



WOOD PULP AND WOOD PULP PAPEES 105 

in two ways, one of which is the ordinary soda process, and 
the other an acid treatment requiring the use of sulphurous 
acid. 

Preparation of the Wood. — The logs of wood are cut up 
and barked exactly as in the case of mechanical pulp. The 
short two-foot pieces are then cut up into small flakes about 
one inch square and half an inch thick by means of a 
machine known as a chipper. This is similar in construction 
to a Hbarker, consisting of a heavy iron disc rotating at a 
high speed inside a stout cover. The disc revolves in a 
vertical position, and three projecting knives slice up the 
logs into flakes. For this purpose the disc is provided 
with three slots which radiate from the centre towards the 
circumference for about 12 inches. The knives can be 
adjusted so that they stand up through the slots and above 
the surface of the disc to any required distance. 

In order to ensure uniformity in the size of the chips, 
the practice is frequently adopted of sifting the wood 
leaving the chipper. The sieve is a large skeleton drum, 
the outer surface of which is made of a coarse wire cloth 
capable of passing all pieces of the size mentioned. Larger 
chips and pieces are retained in the drum as it revolves in 
a horizontal position and only fall out on reaching the 
extreme end of the machine. 

The Digesters. — The object of boiling the wood under 
pressure with chemicals is to dissociate the valuable fibrous 
portion of the plant from the resinous and non-fibrous 
portion. In this process the wood loses half its weight, the 
yield of pulp being about 50 per cent., and the remainder is 
dissolved out by the chemical solution. The conditions of 
treatment are extremely varied in character, the quality of 
the pulp produced varying in proportion. 

The digesters are either spherical, cylindrical, or egg- 
shaped, being constructed to revolve at a slow rate of speed, 



106 



THE MANUFACTUEE OF PAPER 




Fig. 33. — Wood Pulp Digester, partly 
in elevation, partly iu section. 



or fixed permanently in 
an upright position. 
Spherical boilers are 
usually 9 or 10 feet in 
diameter, the cylindrical 
digesters being 40 or 50 
feet high and 12 or 15 
feet diameter, the larger 
ones being capable of 
taking 20 tons of wood 
for each operation. 

For the alkaline pro- 
cess the interior of the 
digester does not require 
any special treatment, 
but with the acid process 
the internal portion of 
the boiler is carefully 
lined with a thick layer 
of acid - resisting brick 
and cement. 

The contents of the 
digester are heated by 
means of high-pressure 
steam, which is blown 
direct into the mass or 
passed through a coil 
lying at the bottom of 
the vessel. In the 
former case the steam is 
condensed by the liquor, 
the volume of which is 
consequently increased, 
while in the latter case 



WOOD PULP AND WOOD PULP PAPEES 107 

the condensed steam is drawn off continuously from the 
pipes. Each system has its own particular advantages. 

Different Kinds of Chemical Wood PaljJ. — According to 
the method of treatment so the quality of the pulp varies. 
The chemicals used, the system of boiling, the temperature 
of digestion, the strength of the solutions, the duration of 
the cooking period, and, last but not least, the species of 
wood, are all determining factors in the value of the ultimate 
product. 

Soda Pulp. — This is prepared by digesting wood with 
caustic soda in revolving boilers for eight or ten hours at 
a pressure of 60 to 80 lbs. 

Sulphate Pulp. — Prepared by digesting the wood with 
a mixture of caustic soda, sulphide of soda, and sulphate 
of soda. 

Sidphite Pulp. — The process most generally adopted for 
the manufacture of wood pulp is the treatment of the 
material in brick-lined digesters with bisulphite of lime for 
eight to nine hours at a pressure of 80 lbs. 

Mitscherlich Pidp. — This is sulphite pulp prepared by 
digesting the wood at a much lower temperature and for a 
longer period than the ordinary sulphite. The steam is 
not blown direct into the mass of wood, and the pressure 
seldom exceeds 45 or 50 lbs., the time of boiling occupying 
45 to 50 hours. So called from the name of the inventor. 

Sidphite Wood Pulp. — This name is given to pulp pre- 
pared by digesting wood with solutions containing sul- 
phurous acid, or salts of sulphurous acid. The acid is 
produced by burning sulphur or certain ores containing 
sulphur, such as copper or iron pyrites, in special ovens. 
The most modern form of oven consists of a cylindrical cast- 
iron drum revolving slowly in a horizontal position on 
suitable bearings. The sulphur is thrown at intervals, or 
fed automatically, into the oven, the amount of air being 



108 



THE MANUFACTUEE OF PAPER 



carefully regulated to avoid the formation of sulphuric acid 
in the later stages of preparation. The sulphur is also 
burnt in stationary ovens which consist of flat shallow 
closed trays. 

The hot sulphurous acid gas passes through pipes and is 
cooled, after which it is brought into contact with water and 







i^g5^ 


'""pHHiiVilHIk^BH 






ii- nil ^ ■ ^'^ ' ■ r' 


r 


%np 




WffP^P^'^iFiJLP . . 


■■ '^^jSlaK^M 


^^ 



Fig. 34. — View of ordinary Sulphur-burning Ovens. 



lime for the production of the bisulphite of lime. This is 
accomplished by one of two methods as follows. 

Tower System. — The cool gas is drawn into high towers 
usually built of wood, 7 or 8 feet diameter, which are 
filled with masses of limestone. From tanks at the top of 
each tower a carefully regulated quantity of water flows 
down upon the limestone and absorbs the ascending column 



WOOD PULP AND WOOD PULP PAPERS 109 

of gas, this being drawn into the tower from the bottom. 
The limestone is simultaneously dissolved, and the liquid 
which flows out from the pipes at the bottom of the tower 
consists of lime dissolved in sulphurous acid, together with 
a certain proportion of free sulphurous acid. This is 
generally known as a solution of bisulphite of lime. 

Tank System. — The somewhat costly tower system has in 
many cases been superseded by the use of a number of 
huge Wooden vats, 10 to 12 feet diameter and 8 to 10 feet 
high. These tanks are filled with water and a known 
quantity of slaked liilie. The gas is forced into the tanks 
by pressure or drawn through by suction, and the conver- 
sion of the milk of lime into bisulphite of lime proceeds 
automatically. In order to ensure complete absorption the 
gas passes through the tanks in series, so that the spent 
gases leaving the vats do not contain any appreciable 
amount of sulphurous acid. 

In order to obtain pulp of uniform quality it is necessary 
that the liquor should be of constant composition. The 
formula differs in the various mills according to the condi- 
tions which are found most suitable. 

Sulphite Digesters. — The almost universal form of boiler 
employed in cooking wood by the sulphite process is a tall 
cylindrical vessel of about 50 feet in height, and 14 to 15 
feet internal diameter, lined with acid-resisting brick. 

This form of digester is capable of holding 20 tons of 
wood at one charge, yielding 10 tons of finished pulp. 

The chipped wood is discharged into the digesters from 
huge bins erected just above the openings to the digesters, 
so that the latter can be filled without any delay and the 
requisite quantity of sulphite liquor added. 

The manhole or cover is at once put on, securely fastened, 
and steam turned on gradually until the pressure reaches 
70 or 80 lbs., at which pressure the cooking is steadily 



110 THE MANUFACTUEE OF PAPEE 

maintained. The progress of the operation is watched and 
samples of the liquor drawn from the boiler at intervals to 
be tested, so that the boiling may be stopped when the 
results of the testing show the wood is sufficiently cooked. 

There is no special difficulty in this operation, provided 
the necessary conditions are observed. It is important 
that the wood should be dry, and that the proportion of 
sulphite liquor per ton of dry wood should be constant. If 
the wood happens to be wet, due allowance must be made 
for the excess water and a somewhat stronger liquor used 
in order to compensate for this. Other precautions of a 
similar character are observed in order to minimise the 
danger of an insufficiently cooked pulp. 

Washing. — When the pulp has been boiled, a process 
which generally occupies seven or eight hours, the steam 
is shut off and the contents of the boiler blown out into 
large vats known as blow-out tanks, the pressure of steam 
remaining in the digester being sufficient to empty the 
softened pulp in a few minutes. Much of the spent 
sulphite liquor, now containing the dissolved resinous and 
non-fibrous portions of the original wood, drains away from 
the mass in the tank, and then copious supplies of clean 
water are added in order to wash out the residual liquors 
which it is essential to remove. 

Numerous other devices are employed to ensure the com- 
plete washing of the boiled pulp. 

Screening. — The production of a high-class pulp necessi- 
tates proper screening to eliminate coarse pieces of unboiled 
wood and the knots, the latter not being softened 
completely. The methods adopted vary according to 
requirements. 

For uniform clean pulp that can be bleached easily the 
material from the blow-out tanks is, after washing, mixed 
with large quantities of water and run through sand traps, 



WOOD PULP AND WOOD PULP PAPERS 111 

which consist of long shallow wide boxes provided with 
slanting baffle-boards to retain knots and large pieces of 
unsoftened wood, the pulp thus partially screened being 
subsequently treated in the proper screening apparatus. 

Sometimes the washed pulp is sent direct to the screens 
and the well-boiled fibres sorted out by a system of graded 
screens, which separate the completely isolated fibres from 
the bulk and retain the larger pieces, these being broken 
dowiT in a suitable engine and put back on the screens. 

The machinery employed for screening chemical pulp is 
identical with that used for the treatment of mechanical 
wood pulp. 

Finishing. — The ordinary sulphite pulp is worked up 
into the form of dry sheets for the market and not sent out 
in a wet state as the mechanical wood. There are several 
practical disadvantages in preparing the latter in a dry 
condition which do not, however, occur with chemical 
pulp. 

Hence the pulp after being screened is not pressed but 
submitted to a different process. From the screens the 
mixture of pulp and water, the latter being present in large 
quantity, is pumped into a concentrator, or slusher, as it is 
termed, by means of which some of the water is taken out. 

The slusher consists of a wooden box divided into two 
compartments by a vertical partition. In the larger compart- 
ment a hollow drum covered with a fine wire cloth revolves, 
the construction and purpose of which are precisely the same 
as that of the wet press machine used for mechanical pulp. 

As the drum revolves the pulp adheres to the outer 
surface, while the water passes through the wire cloth. 
The drum is not completely immersed in the mixture, so 
that the skin of pulp is brought out of the water by the 
rotation of the drum. When this takes place the contact of 
a wooden or felt covered roll which revolves on the top of 



112 THE MANUFACTUEE OF PAPEE 

the drum causes the pulp to be transferred from the drum 
to the roll. The wet pulp is continuously scraped off by an 
iron bar or doctor, as it is called, resting on the surface of 
the roll, and it finally drops into the second comj)artment 
of the slusher in a more concentrated form ready for the 
drying machine. 

Drying. — The mass of wet pulp from the slusher is con- 
veyed into a circular reservoir or stiif chest, which serves to 
supply the machine used for converting the pulp into dry 
sheets. 

The machine is to all intents and purposes a Fourdrinier 
paper machine, and the process is similar to that used for 
the manufacture of paper. The pulp flows in a continuous 
stream on to a horizontal endless wire, which carries it 
forward as a thin layer; the water drains through the 
meshes of the wire, further quantities being removed by 
suction boxes, which draw away the water by virtue of the 
vacuum produced by special pumps. The wet sheet then 
passes between the couch rolls which compress the pulp, 
squeezing out more water, and then through jj?-ess rolls, 
which finally give a firm adherent sheet of pulp containing 
70 per cent, of water. The sheet is dried by passing over 
a number of steam heated cylinders, which cause all the 
moisture to evaporate from the pulp. At the end of the 
machine the dry pulp is cut up into sheets of any con- 
venient size, and packed up in bales of two or four cwts. 

Mitscherlich Sulpldte Pulp. — This term is applied to 
sulphite wood prepared by submitting the chipped wood 
to a comparatively low pressure for a long period. The 
wood is placed in the stationary upright form of digester 
with the requisite amount of liquor, and the heating pro- 
duced by the passage of steam through a leaden coil lying 
at the bottom of the digester, so that the steam does not 
condense in the liquor but in the coil, from which it is 



WOOD PULP AND WOOD PULP PAPEES 113 

drawn off. The pressure seldom exceeds 45 lbs. but the 
duration of the cooking is thirty-six to forty-eight hours. 
The boiler is not emptied under pressure, but the pulp is 
discharged from the digester after the pressure has been 
lowered, and the manhole taken off. The contents are 
usually shovelled out by the workmen. 

The pulp is carefully washed, screened and made up into 
wet sheets on the ordinary wet press machine. This pulp 
is never dried on the Fourdrinier like the common sulphite, 
as its special qualities can only be preserved by the treat- 
ment described. This pulp is particularly suitable for 
parchment papers, grease proofs and transparent papers. 

Soda Wood Pulp. — The chipped wood is boiled in 
stationary or revolving digesters for eight or nine hours at 
a pressure of 70 or 80 lbs. A solution of caustic soda 
is employed, about 16 to 20 per cent, of the weight 
of the wood being added to the contents of the digester. 
Live steam is blown direct into the mass, and after the 
operation the spent liquor is carefully kept for subsequent 
treatment. The pulp is washed in such a manner that the 
amount of water actually used is kept down to the smallest 
possible volume consistent with a complete removal of 
soluble matters. This is done in order that the spent 
liquors may be treated for the recovery of the soda. 

Recovery of Spent Liquors. — When wood is cooked by the 
soda and sulphate processes the solutions containing the 
dissolved organic matter from the wood can be evaporated, 
and the original chemical recovered. In the case of soda 
pulp the method of treatment is as follows : the spent 
liquors and the washings are evaporated by means of a 
multiple effect vacuum apparatus to a thick syrup. The 
concentrated liquor produced is then burnt in special 
furnaces, all the organic matter being consumed, leaving a 
black mass which consists mainly of carbonate of soda. 

p. I 



114 



^HE MANUFACTURE OF PAPER 



The mass is washed with water to remove the carbonate 
which is afterwards converted into caustic soda by being 
boiled with lime. 

The spent liquors from the sulphite process have no 




Fig. 35. — Spruce Wood Pulp. 

value, for they cannot be recovered by this method. At 
present the whole of the sulphur used and the organic 
matter dissolved from the wood is lost. This means the 
loss of about 250 to 350 lbs. of sulphur and nearly 50 per 
cent, of the weight of wood for every ton of pulp produced. 



WOOD PULP AND WOOD PULP PAPEES 115 

Wood Pulp ; Microscopic Features. 

Mechanical and chemical pulps are readily distinguished 
under the microscope. The former consists of fibres of 




Fig. 36. — Mechanical Wood Pulp. 

irregular shape and size, mixed with a large proportion of 
structureless particles, all bearing evidence of having been 
torn apart and separated by mechanical methods. The 
chemical pulp, on the other hand, consists of fibres isolated 
by a process which preserves them in perfect condition and 

I 2 



116 THE MANUFACTUEE OF PAPEE 

form. The pulp from the various woods can be differentiated 
by minute details in fibre structure, some of the woods being 
determined from the presence of characteristic cells. 

The use of aniline sulphate can also be resorted to, and 
for microscopic work the most useful reagent is a mixture 
of zinc chloride and iodine. This produces an intense 
yellow colour with mechanical pulp and a bluish colour 
with sulphite and other chemical wood pulps. 

The Daily Newspaper.. 

The newspapers of the present day are made almost 
exclusively of wood pulp. The use of the latter material 
for paper-making has steadily increased from the date of 
its introduction about a.d. 1870, when wood pulp was 
imported into England in considerable quantities. 

News and cheap printings consist of mechanical and 
chemical wood pulps mixed in varying proportions deter- 
mined chiefly by the price paid for the finished paper. In 
some cases the proportion of mechanical wood pulp is as 
much as 85 per cent., though the average composition of a 
cheap wood paper is represented by the following propor- 
tions : Mechanical pulp, 70 per cent. ; sulphite pulp, 20 per 
cent. ; loading, 10 per cent. 

Some idea of the enormous quantity of material used for 
the daily press may be judged from one or two examples. 
A certain popular weekly newspaper having a circulation of 
one and a quarter million copies per week requires every 
week 137 tons of paper produced from 170 tons of wood. 
A popular halfpenny newspaper boasting a circulation of 
about one-half million copies per day consumes 185 tons 
of paper manufactured from 230 tons of wood, every week. 

It is easy also from these facts to estimate the amount 
of timber which must be cut down to supply the demand 
for newspapers and cheap printings. 



WOOD PULP AND WOOD PULP PAPERS 117 

The manufacture of news calls for considerable skill and 
able management, owing to the keen competition amongst 
the paper mills devoted to this class of paper. The process 
as carried on in England is as follows : — 

The mechanical pulp, reaching the mill in the form of 
thick sheets suitably packed up into bales, is first broken 
up again into moist pulj). Various machines are used for 
this, such as Wurster's kneading engine, Cornett's breaker, 
or some similar contrivance. An old potcher, such as is 
used for the breaking and washing of rags, makes a good 
pulp disintegrator. The broken pulp is discharged into 
beating engines in any suitable or convenient manner and 
the right proportion of chemical wood pulp added in the 
form of dry sheets. The beating process only occupies 
thirty to forty minutes in the case of the common news, 
a marked contrast to the eight or nine hours required by 
rags. China clay is added to the contents of the beater, 
ten to twelve per cent, being the general practice. This is 
followed by a measured quantity of rosin size, and after 
thorough incorporation the size is precipitated upon the 
fibres by means of alum. 

In the commoner qualities of these papers the materials 
are added in the dry state, but for finer grades of news- 
paper the china clay is mixed with water, and carefully 
drained through a fine sieve before use. The alum cake is also 
dissolved and treated in a similar manner in order to keep out 
dirt and coarse particles likely to produce holes in the paper. 

The paper machine used for the manufacture of cheap 
printings is constructed to produce as much as 100 to 180 
tons of finished paper per week, every detail being arranged 
for a large output at a very high speed. In the modern 
machine it is possible to produce paper at the rate of 
450 to 550 feet per minute, the width of the sheet being from 
120 to 160 inches. 



118 



THE MANUFACTUEE OF PAPEE 



Careful attention is paid to economy of every kind with 
regard to the power required for driving the machine, the 
amount of steam consumed in di-ying the paper, recovery 
of excess of fibre and china clay which escapes from the 
machine wire, and similar details of a mechanical order. 




Fig. 37. — The Screens for removiug Coarse Fibres from Beaten 

Pulp. 

The beaten pulp, after being sized and coloured, is 
discharged into huge circular brick tanks, or stuff chests, 
two of which are found with each paper machine. The 
supply of pulp and water for the machine is taken from 
one stuff chest while the second is being filled up from the 



WOOD PULP AND WOOD PULP PAPEES 



119 




120 THE MANUFACTUEE OE PAPER 

beating engines, in order to secure a mixture of constant 
composition. 

The pulp is pumped from the stuff chest into a small 
regulating box placed above the machine wire, and this box 
is kept full of beaten pulp so that the supply of pulp and 
water to the machine is perfectly constant. The pulp, 
diluted with the proper quantity of hack-ivater, is carefully 
strained through rotary screens and allowed to flow through 
a distributing box on to the machine wire, where it rapidly 
forms a sheet of paper. 

The excess of water, together with a certain proportion 
of fine fibre and china clay, falls through the wire, and is 
caught below in a shallow box, called the save-all. This 
back-ivater, as it is called, is used over again for diluting 
the beaten pulp to the right consistency, as already 
described. 

The whole of the water obtained in this way is not all 
utilised in the regulating box, and any surplus is pumj)ed 
up continually into large store tanks and used in the 
beating engines for breaking down the dry pulp. 

In many cases, where a large quantity of water is used 
on the machine, special methods have to be adopted for the 
recovery of all the fibre and clay, which would otherwise 
be lost, and there are many ingenious systems in use 
whereby this saving is effected. 

The most usual practice is to allow the excess of water, 
which contains from 8 to 15 lbs. of suspended matter per 
thousand gallons, to flow through a series of brick tanks at 
a slow rate of speed. The clay and fibre settle to the 
bottom of the tanks, and the water passes away from the 
last tank almost clear and free from fibre and loading. 

The drying of the moist paper leaving the press rolls of 
the machine is effected in the usual manner by means 
of drying cylinders. On account of the great increase of 



WOOD PULP AND WOOD PULP PAPERS 121 

speed at which the paper is produced, the number of dry- 
ing cyhnders has also been increased, and at the present 
time a machine of this description is provided with 28 or 
32 cylinders, the object being to dry the paper economically- 

Mechanical Wood Pulp in Paper. 

The presence of mechanical wood pulp in paper is 
dete(fted by means, of several reagents, which produce a 
definite colour when applied to a sheet of paper containing 
mechanical wood. The dejpth of colour obtained indicates 
approximately the percentage present, but considerable 
practice and experience is necessary to interpret the colour 
exactly. A more reliable method of estimating the per- 
centage of mechanical wood in a paper is by microscopic 
examination. 

The reagents which can be used are — 

(1) Nitric Acid. — This produces a brown stain on the 
paper, but it is not a desirable reagent for ordinary office 
purposes. 

(2) Aiiiline Sidpliate. — A solution of this is prepared by 
dissolving 5 parts of aniline sulphate in 100 parts of dis- 
tilled water. When applied to the surface of news a yellow 
coloration is produced, more or less intense according to 
the amount of mechanical wood present. It can only be 
used with white papers, or papers very slightly toned, 

(3) Pldoroglucine. — This sensitive reagent, which gives 
a rose-pink colour when brushed on to the surface of the 
paper, is prepared by dissolving 4 grammes of phloro- 
glucine in 100 c.c. of rectified spirits, and adding to the 
mixture 50 c.c. of pure concentrated hydrochloric acid. 

There are several other aniline compounds which give 
colour reactions of a similar character, but they are not 
often used. The phloroglucine reagent fails as a test for 



122 THE MANUFACTURE OE PAPER 

mechanical wood in papers which have been dyed with 
certain aniline colours, for example, metanil yellow. 
Paper which has been coloured with this dye will, when 
moistened with the phloroglucine reagent, give an intense 
pink colour, even if no mechanical wood is present. This 
is due to the fact that the dye itself is acted upon by the 
hydrochloric acid in the test reagent. The same colour is 
produced on the jpaper with hydrochloric acid per se. 

There is little difficulty in distinguishing between the 
colour arising from the presence of such a dye, because 
the effect is instantaneous, whereas the coloration due 
to mechanical wood develops gradually. Moreover, the 
reaction due to the presence of metanil yellow gives a 
perfectly even coloured surface, whereas with mechanical 
wood pulp the fibres appear to be more deeply stained than 
the body of the paper. 

Output of a Paper Machine. — The quantity of paper 
which can be produced on the paper machine is readily 
calculated from the following data : — 

Speed of machine in feet per minute F 

Nett deckle width in inches D 

Width of sheet of paper in inches W 

Length of sheet of paper in inches L 

Number of sheets in ream 8 

Weight of paper per ream R 

The general formula for the output of paper per hour is 

P, , , . „ , 720 X J^ X D X i? 
Output m lbs. per hour = p 777 — . 

Wlien the number of sheets in the ream is 480, this 
formula simplifies to 

Output in lbs. per hour 



n X R X F X B 



L X W 

The term " nett deckle width " applies to the width of 



WOOD PULP AND WOOD PULP PAPERS 



123 




o 

6c 



m 
m 

60 



Ah 



2) 

M 



124 THE MANUFACTUEE OF PAPEE 

the trimmed finished paper at the end of the machine. 
The formula takes no account of the allowance required for 
trimming edges. In most cases the deckle width of the 
machine is arranged so that the paper is cut into strips of 
equal width when leaving the calenders, e.g., a deckle of 
80 inches will give 4 sheets, each 20 inches wide. 

The method by which the general formula is obtained 
may be explained by an example. 

What is the output of a machine having a speed of 
100 feet per minute, with an 80-inch deckle, producing a 
sheet of paper 20 inches by 30 inches, weighing 30 lbs. per 
ream of 480 sheets ? 

The machine produces every minute a sheet of paper 
100 feet long and 80 inches wide. 

Hence output per minute in square inches 
= 12 X 100 X 80. 
Output per hour in square inches 
= 60 X 12 X 100 X 80. 

Now each (20 x 30 X 480) square inches is area of 
one ream. 

Output of paper per hour in reams 

_ 60 X 12 X 100 X 80 
~ 480 X 30 X 20 • 
Output of paper per hour in lbs. 

_ 720 X 100 X 80 X 30 
■~ 480 X 30 X 20 

= 600 lbs. 

The general formula may be applied for the purpose 
of calculating the speed at which the machine must be 
driven. 

Example. — A machine with 75-inch deckle is required to 
produce 6 cwts, per hour of a paper 25 inches by 18 inches 



WOOD PULP AND WOOD PULP PAPEES 125 

(500 sheets), weighing 19 lbs. to the ream. At what speed 
is the machine to be driven ? 
Output in lbs. per hour 

120 X F X D X n 



672 = 



S X L X W 
720 X i^ X 75 X 19 



500 X 18 X 25 

F = 148 feet per minute. 



CHAPTER VI 



BROWN PAPERS AND BOARDS 



Common Broivns. — The raw material used in the manu- 
facture of common brown papers is chiefly jute and waste 
fibres of every description, such as waste cuttings from 
boxboard factories, old papers, wood pulp refuse, and other 
substances of a like nature. The jute, in the form of sack- 
ing or old gunny bags, and the hemp refuse, in the shape 
of old rope and string, are subjected to a slight chemical 
treatment just sufficient to isolate the fibres to a condition 
in which it is possible to work them up into paper. The 
bagging and string are cut up in a rag chopper and boiled 
in revolving boilers with lime or caustic soda for several 
hours at a pressure of 20 — 30 lbs., the lime being used when 
it is desired to manufacture a harsh paper, and the caustic 
soda being employed for the production of paper having a 
softer feel. The pulp is not always washed very com- 
pletely after the process of digestion, as is the case with 
white papers, and it is often j)Ossible to extract from brown 
papers of this class a considerable proportion of the alka- 
line matter which has not been thoroughly removed from 
the boiled pulp. The presence of this alkaline residue does 
not affect the quality of ordinary brown paper, but is 
frequently a serious defect in the case of middles or straw 
boards, which are afterwards utilised for boxes and covered 
with coloured papers. The colour of the paper pasted on 
to such incompletely washed boards is frequently spoilt by 
the action of the alkali when moistened with the paste 



BEOWN PAPERS AND BOAEDS 127 

used, many aniline dyes being susceptible to the small 
proportion of alkali present. 

The stronger materials, such as jute or old rope and string, 
are either used by themselves or blended with inferior raw 
material according to the quality of the paper being made. 
The Jute and hemp fibres are generally beaten by themselves 
in the engine before the other materials are added. The 
pulp is mixed with the required amount of loading, while 
the sizing and colouring operations are carried out in the 
usual way. 

The common brown papers are known by a variety of 
trade names which at one time indicated the nature of the 
fibrous constituent, but at the present day the name is no 
guide or indication of the material used for the manufacture 
of the paper. The common heavy brown used for wrapping 
sugar and sundry groceries made in heavy grey and blue 
shades is a coarse paper made from cheap materials and 
containing a large proportion of mineral matter. It is 
usually supplied under the trade name of royal. 

A somewhat lighter and stronger wrapping paper of a 
white or buff colour, used for wrapping groceries, tea, and 
cotton goods, is that known as casings, a name probably 
derived from the application of this paper originally to the 
lining of cases. 

Manila papers so called were originally made from 
rope, but the term is now applied to papers which may be 
made entirely of wood pulp. 

Rope hroicns are common papers made of fairly strong 
material of a miscellaneous character, this name having 
been derived from the fact that rope and similar fibre were 
at one time used exclusively. 

Wood Pulp Wrappers. — Most of the papers of the present 
day are made from wood pulp, this material giving a thin, 
light, tough paper, which is pleasant to handle and forms a 



128 THE MANUFACTUEE OF PAPEE 

great contrast to the dense, opaque, heavily loaded, and 
inartistic specimens produced some years ago. Paper of 
this kind, though apparently more expensive than common 
browns, is really more economical in use. The paper is not 
only stronger, but it is possible to obtain a larger number 
of sheets for a given weight. The great advantage in the 
improvement of brown papers dates from the introduction 
of the now well-known kraft papers, which are of compara- 
tively recent origin. 

Kraft Paper. — The term Kraft, meaning " strength," is 
applied to a remarkably strong cellulose paper prepared from 
spruce and other coniferous woods by the soda treatment, 
the special feature of the process being an incomplete 
digestion of the wood. 

The wood previously chipped into pieces 1 inch to 1^ 
inches in length, is boiled with caustic soda, the digestion 
being stopped before the wood pulp has been quite softened, 
and while the pulp is still too hard to be broken up into 
isolated fibres by simple agitation in water. The pulp after 
thorough washing is disintegrated by means of an edge- 
rtinner, or some form of breaking engine, the first mentioned 
probably giving the most satisfactory results, and converted 
into paper by the usual methods. 

The wood can also be reduced by the sulphate process, in 
which case the chipped wood is boiled in a liquor to which 
about 25 per cent, of spent lye from a previous cooking is 
added. 

The best results are obtained by attention to the cooking 
process to ensure an under-cooked pulp, by careful isolation 
of the fibres in a kollergang, or edge-runner, which machine 
is capable of separating the fibres without shortening them, 
and by proper manipulation on the paper machine. 

The paper produced under favourable conditions in this 
direction is wonderfully tough and strong and may be 



BROWN PAPEES AND BOAEDS 129 

quoted as the most recent example of the fact that the 
latent possibilities of wood pulp have by no means been 
exhausted or even thoroughly investigated. 

Imitation Kraft Paper. — If wood is boiled in water at 
high temperatures the fibre is softened and much of the 
resinous matter is removed. Such wood, if ground in the 
same way and by the same methods as ordinary mechanical 
wood pulp, is readily disintegrated, and a long-fibred pulp 
may*be obtained. The process of boiling short 2 feet logs 
of wood in a digester under a pressure of 20 — 50 lbs. has 
long been known. The wood after boiling is partly washed 
and then worked up into pulp by the usual mechanical 
process. The wood is easily ground and yields pulp con- 
taining long fibres which in their physical properties 
closely resemble those of pure wood cellulose, but the 
original constituents of the wood are present almost 
unchanged, just as in mechanical pulp. The product 
obtained by grinding is a very tough flexible material of a 
brownish yellow colour, and the paper is known as Nature 
brown. It is chiefly used for the preparation of tough 
packing papers, for the covers of cheap pocket-books, and 
other miscellaneous purposes. When this brown mechanical 
wood pulp paper is glazed on both sides it is then known as 
ochre glazed, the word ochre referring to the colour. When 
made up into light weight papers it is sold as imitation 
Jcraft payjer. 

A great variety of wrapping papers are now made from 
wood pulp, such as sealings, sulphite browns, manilas, sulphite 
caps, but the distinctions between these papers relate chiefly 
to the amount of finish, the colour and size of the sheet. 
The methods of manufacture only differ in small details as 
indicated by these distinctions. 

Fine Wrappings. — The papers used for packing small 
goods such as silver ware and other delicate articles are 

V, K 



130 



THE MANUFACTURE OF PAPER 



generally tissues, the better qualities of which are made 
from rag, and the cheaper qualities from wood pulp. 
These papers are known as tissue, crepe, crinkled tissue, 
manila tissue, and by a variety of trade terms. 




Fig. 40. — Single Cylinder or Yankee Machine. 

Many of the fine wrappings of the tissue class and the 
somewhat heavier papers known as M. G. Caps are manu- 
factured on the single cylinder machine, which produces a 
paper having a highly polished surface on one side and a 
rough unglazed surface on the other side. 

In the single cylinder machine the beaten pulp passes 



BEOWN PAPEES AND BOAEDS 



131 



from the stuff-chest on to the whe of the ordinary Four- 
drinier machine and through the press rolls, but instead of 
being dried over a number of cylinders the paper is led 
over one single cylinder of very large diameter which is 
heated internally with steam. The paper is usually pressed 
against the surface of the cylinder by means of a heavy 
felt, which is, however, sometimes omitted. The side of the 




Fig. 41. — Section of Wet Press, or Board Machine. 



paper coming into contact with the cylinder becomes highly 
polished, the surface in contact with the felt remaining in 
an unfinished rough condition. This paper is said to be 
machine glazed and is laiown as an M. G. paper. 

Boards. — Cards, millboards, middles, boxboards, carriage 
panels, and similar paper products are manufactured either 
on a single board machine, by means of which single 
sheets of any required thickness can be obtained, or on a 

K 2 



132 THE MANUFACTUEE OF PAPEE 

cotitinuous hoard machine, which is capable of producing 
cards and plain or duplex boards of moderate thickness. 

The raw material used consists, as in the case of browns 
and wrappers, of every conceivable fibrous substance mixed 
with mineral matter and then suitably coloured. The 
preliminary processes for the treatment of the pulp are 
exactly the same as those employed in the case of brown 
papers up to the point at which the beating has been effected. 

Single Board Machine. 

The beaten pulp, diluted with large quantities of water, 
is pumped continuously into a large wooden vat of rect- 
angular shape. Inside this vat revolves slowly a hollow 
cylindrical drum, the circumference of which is covered 
with wire gauze of fine mesh. The drum is not completely 
immersed in the mixture of pulp and water, so that as it 
revolves the water passes through the wire, while the pulp 
adheres to the surface. The water flows regularly into the 
interior of the drum and runs away through pipes fitted at 
each side of the vat near the axis of the drum, and the pulp 
is brought up out of the water until it comes into contact 
with a travelling felt. The thin moist sheet of pulp 
adheres to this felt, passes through squeezing rolls which 
remove part of the water, and is finally carried between two 
wooden or iron rollers of large diameter. The pulp adheres 
to, and is wound up on the upper roller, the felt being 
carried back by the lower roller to the vat. When the 
sheet on the upper roller has attained the desired thick- 
ness, it is immediately cut off and transferred to a pile of 
similar sheets, a piece of coarse sacking or canvas being 
interposed between every wet board. The dimensions of the 
full-sized board are determined by the diameter of the upper 
roller and its length. A roll 74 inches wide and 14 inches 
diameter will give a board 74 inches by 44 inches. 



BEOWN PAPERS AND BOAEDS 



133 



As soon as a sufficient number of wet boards has been 
obtained they are submitted to pressure in order to remove 
the excess of water and at the same time compress the 
material into dense heavy boards. The pieces of sacking 
are then taken out and tbe boards dried by exposure to air 
at the ordinary temperature or in a heated chamber. 




Fig. 42. — Double Cylinder Board Machine. 

The dried boards are finished off by glazing rolls. These 
rolls compress the boards still further and impart a polished 
surface. The amount of " finish " may be varied by the 
pressure, number of rollings, temperature of the rolls, and 
by damping the surface of the dry boards just before they 
are glazed. The boards are cut to standard sizes before or 
after glazing. 



134 THE MANUFACTURE OE PAPER 

Duplex Boards. — If the single board machine is fitted 
with two vats instead of one, it is possible to manufacture a 
board with different coloured surfaces. A board coloured 
red on one side and white on the other is manufactured by 
having one vat full of pulp coloured red and the second vat 
full of white pulp. The thin moist sheets from the two 
vats are brought together and passed through the glazing 
rolls, which cause the moist sheets to adhere closely to one 
another, the double sheet of pulp so formed being wound up 
on the rollers at the end of the machine. The board is then 
dried, glazed, and finished in the usual way. 

The same principle is occasionally adopted on the 
Fourdrinier machine for duplex wrappers. Thus a 
common brown pulp is worked up in conjunction with 
a dyed pulp to produce a brown j^aper having one surface 
of good paper suitably coloured. The brown pulp flows on 
to the wire of the paper machine, and after it has been 
deprived of part of the water at the suction boxes, a thin 
stream of coloured puljp, diluted to a proper consistency, 
flows from a shallow trough, placed across and above the 
wire, on to the wet brown web of paper in such a manner 
as to completely cover it as a thin even sheet of coloured 
pulp. The adhesion of the latter to the surface of the 
brown paper is practically perfect, and the weight of the 
couch and press rolls ensures uniform felting of the fibres. 

Middles. — This term is applied to a thin or thick card- 
board made of common material, the colour and appearance 
of which is of little importance for inferior goods. 
Boards of this kind are covered subsequently with papers 
of all colours and qualities, and the origin of the word 
" middle " is easily seen. The manufacture of a board 
consisting of two outside papers of good material and a 
middle produced from common stuff is effected by the 
continuous boxboard machine, unless the board is too 



BEOWN PAPEES AND BOAEDS 135 

thick to be passed over drying cylinders, calendered, and 
reeled, in which case the boards are produced on an 
ordinary wet machine and the paper pasted on the surface 
of the dry board. 

The term is, however, now also applied to a common 
paper made of mechanical wood pulp with perhaps a little 
chemical pulp, used for tram tickets, cheap advertising- 
circulars, common calendar cards, and similar purposes, 
to wRich no outer surface of a special character is added. 

Continuous Board Machine. 

This machine differs from the single board machine in 
that the finished board can be produced from the pulp at 
one operation. It is used principally for cards and boards 
of moderate thickness which can be wound up in the form 
of a reel at the end of the machine. 

The mixture of pulp and water is pumped into two or 
more vats and formed into a number of thin sheets, which 
are all brought together between squeezing rolls and passed 
through heavy press rolls which compress the several 
layers into a compact mass. The thick sheet obtained is 
dried over steam-heated cylinders which are placed at the 
end of the press rolls, and calendered. The whole process, 
indeed, resembles that of ordinary paper-making, the main 
difference being the method of producing the wet sheet or 
card. 

Some machines are constructed with six or seven vats 
and forty to fifty drying cylinders, and are capable of 
turning out a large quantity of finished material. 

The board can be made of uniform quality and texture 
throughout, or be finished off with high-grade paj^er on one 
or both sides. In the latter case the constituents of the 
"middle" part are waste papers and raw material of 
inferior quality, the outer surface of wood pulp, white or 



136 THE MANUEACTUEE OE PAPER 

coloured according to circumstances. The variety of papers 
and boards which can be produced is due to the fact that 
the several vats of pulp are independent of one another and 
can be filled with any kind of paper stock. The combined 
sheets forming the ultimate board are dried on the ordinary 
cylinders, calendered, and reeled up at the end of the 
machine. 



CHAPTEK VII 

SPECIAL KINDS OF PAPER 

There are many varieties of paper products obtained by 
submitting finished paper to a number of special pro- 
cesses. Of these only a few of the more important will 
be described. 

These products can be divided approximately into three 
classes : — 

(1) Papers coated on one side or both sides with various 
substances, such as " art," photographic papers, etc, 

(2) Papers impregnated with chemicals, such as blue 
print, medicated, and cheque papers. 

(3) Paper pulp converted into modified products by 
chemical treatment, such as vulcanised board, viscoid, etc. 

Of the first class, the coated papers used for art and 
chromo illustrations are the most important. 

Of the second class, the blue prints and papers impreg- 
nated with chemicals, chiefly employed for the production 
of engineers' drawings, may be regarded as typical. 

In the third class, vegetable parchment and vulcanised 
board are the most familiar. 

Parchment Paper. — This is produced by the action of 
sulphuric acid upon ordinary paper, the most suitable for 
this purpose being made from unsized cotton rag, free 
from such additions as mechanical wood pulp. The 
presence of the latter substance should be avoided, as it 
is liable to char or burn, so that in the finished product it 



138 



THE MANUFACTURE OF PAPEB 



shows itself in the form of small holes. The process 
depends upon the power of sulphuric acid to change the 
surface of the paper into a gelatinous mass, which has 
been shown to consist of a substance called amyloid. 

The best parchment is made from pure cellulose such as 
rag or chemical wood pulp. The quality of the parchment 
depends upon attention to the strength of the acid, the 
temperature of the acid bath, the period of immersion, 
the complete removal of the acid, and the careful drying of 
the wet parchment. 

The acid is employed at a strength of 1'71 specific 




Fig. 43. — Apparatus for making Parclimeiit Paper. 

gravity, being prepared by dikiting the commercial con- 
centrated acid in a leaden vessel, with a sufficient quantity 
of water. 

The parchment is generally prepared by passing a 
continuous sheet of paper through a bath of acid of the 
proper strength at a speed which ensures the correct 
period of immersion. As the treated paper leaves the 
bath it passes through squeezing rolls which remove the 
excess of acid, and the paper is then led through a series 
of tanks containing fresh water, the last traces of acid 
being neutralised by small additions of ammonia, or some 
alkali, to the last washing tank. The wet parchment is 
then passed through suitable rollers and carefully dried 
over cylinders heated internally by steam. The paper is 
l\ept perfectly stretched as it dries, because it shrinks 



SPECIAL KINDS OF PAPER 139 

enormously, and would otherwise become cockled and 
uneven. 

Thick sheets of parchment paper are frequently made 
by passing three sheets of paper through the acid bath and 
bringing them together between the rollers before washing. 
The sheets unite when pressed together ; the remainder of 
the process being the same as that employed for single 
sheets. ■ 

The parchment exhibits remarkable differences to the 
original paper, the strength being increased three or four 
times, the density about 30 per cent., the latter being shown 
by the shrinkage, which amounts to at least 30 per cent. 

Vulcanised Pa'per. — Zinc chloride has the property of 
parchmentising paper in a manner similar to sulphuric acid. 
The product obtained when this reagent is used is generally 
termed vulcanised fibre. The paper is passed as a continuous 
sheet into a bath of strong zinc chloride, having a density 
of 160 — 170 Twaddell, which causes the cellulose to swell 
up and partly gelatinise. A very large excess of strong 
zinc chloride is necessary, and the process is only rendered 
commercially possible by careful recovery of the zinc from 
the washing waters, which are submitted to chemical 
treatment. 

The vulcanised product is subsequently treated with 
nitric acid or with a mixture of nitric and sulphuric acids 
to render them waterproof. Dextrin is frequently employed 
to retard the chemical action to permit of the necessary 
manipulation of the material before it is finally washed. 
The complete removal of the excess of zinc and acid is a 
necessary feature of the whole operation. 

Willesden Paper. — When paper is passed through an 
ammoniacal solution of copper oxide, a superficial gelatinisa- 
tion of the surface takes place, so that the paper when 
washed and dried is impregnated with copper oxide, wliich 



140 



THE MANUFACTURE OF PAPER 



helps to preserve it, and it becomes waterproof. Such 
material is well known as Willesden paper. 

Blue Print or Cyanotype Papers. — This name is usually 
given to the process by means of which blue prints of 
engineers' and architects' plans can be reproduced. It was 
discovered in 1842 by Sir John Herschel. It is a useful 
method of reproducing drawings, and incidentally is of 
great value to the amateur photographer because of the 
facility with which it can be applied for getting proofs 
from negatives quickly and easily without special baths 
and chemicals. The process is based upon the reduction 
of a ferric salt to the ferrous condition by light, and the 
formation of Prussian blue by the action of potassium 
ferricyanide. The negative cyanotype gives white lines 
on a blue ground. Various formulae are in common use. 



- 


Herschel. 


Clark. 


Watt. 


Rockwood. 


Solution 1. 










Potassium ferricyanide 


16 


27 


48 


10 


Water .... 


100 


100 


100 


100 


Ammonia 


— 


2-3 





— 


Saturated solution of 










oxalic acid . 


— ■ 


20 


— 


— 


Solution 2. 










Ammonia- citrate of iron . 


20 


30 


50 


30 


Water .... 


100 


100 


100 


100 


Boric acid 


— 


— 


0-5 


— 


Dextrin .... 


— 


— 


— 


5 



Equal parts of the two prepared solutions are mixed 
when required and spread evenly over well-sized paper. The 
paper is hung up, dried, and preserved in a dark dry place. 

The positive cyanotype gives blue lines on a white ground, 
being the reverse of the ordinary blue print. That is, no 
image is formed where the light acts, and the reaction is 



SPECIAL KINDS OF PAPEE 



141 



the formation of blue due to the union of a ferrous salt 
with ferrocyanide of potassium. 

Pizzighelli in 1881 gave the following formula : — 



Water 
Gum arabic 

Ammonia-citrate of iron 
Ferric chloride . 
Potassium ferrocyanide 



Solution 1. Solution 2. Solution 3. Solution 4 



100 

20 



100 
50 



100 
50 



100 



20 



Mix the first three solutions in the following order in the 
proportions stated : — 

Solution 1. 20 parts. 
Solution 2. 8 „ 
Solution 3. 5 ,, 

As soon as the solution, which at first gets thick and 
cloudy, is clear and thin, it is spread over the surface of 
well-sized paper, which is then dried in a warm room. 

The print, which appears yellow on a dark yellow ground, 
is treated with the developer (solution 4) by means of 
a brush dipped in the solution. When the image is deep 
blue in colour, the print is washed in water and then placed 
in dilute hydrochloric acid (1 part of acid to 10 parts of 
water) till the ground is quite white. A final washing with 
water is then necessary. 

Waterhouse gives the followina; formula : — 



- 


Solution 1. 


Solution 2. 


Solution 3. 


Solution 4. 


Water .... 


650 


150 




100 


Gum arabic 


170 


— 


— 


— 


Tartaric acid 


— 


40 


— 


— 


Ferric chloride solution 45° 










Beaume .... 


— 


— 


150 


— 


Ferrocyanide of potassium 


— 


— 


— 


20 



142 THE MANUFACTUEE OF PAPEE. 

Solutions 1 and 2 are mixed and No. 3 added gradually 
with constant stirring. The mixture is left twenty-four 
hours, and diluted with water to a specific gravity of 1*100. 

The j)aper is coated with the solution and used as ali-eady 
directed, being developed in ferrocyanide of potassium 
solution and washed with water, treated with weak hydro- 
chloric acid, and then finally cleaned fi-om all traces of 
acid. 

Black Lines on a White Ground. — This modification of 
the ordinary blue print is arrived at with the following 
formula : — 

Water 96-0 parts. 

Gelatine ...... 1*5 ,, 

Perchloride of iron (in syrupy condition) 6*0 ,, 
Tartaric acid ..... 6*0 ,, 

Sulphate of iron . . . . . 1*5 ,, 

The paj)er is coated with the solution. After printing, 
the image is developed with a solution containing 

Gallic acid ... 1 part. 

Alcohol . . . .10 parts. 

Water . . . . 50 „ 
A final washing of the print with water completes the 
operation. 

Coated Papers. 

This term should properly include all the varieties of 
special papers which are coated with extraneous matter for 
particular purposes, such as art, chromo, tinfoil, gilt, emery, 
carbon, photographic, marble, and sand papers. In j)ractice 
however, the term is almost entirely limited to "art" 
papers used for illustration work and half-tone printing. 

An "art" paper, using the definition given above, con- 
sists of an ordinary sheet of paper, one or both sides of 



SPECIAL KINDS OF PAPER 



143 



which have been coated by the application of a mixture of 
a mineral matter, such as china clay or satin white, and 
some adhesive, like casein or glue. The object of the coat- 
ing is to impart to the paper a perfectly smooth surface, 
rendered necessary because of the conditions under which 
the printing of the illustrations is carried out. 




EiG. 44.— General arrangement of Plant for making " Art " Paper. 

The machine used for coating the paper consists of a 
large hollow drum about 40 inches diameter and 48 inches 
wide. The paper is brought over upon the drum in a con- 
tinuous sheet, and the coating mixture applied to the surface 
by means of a revolving brush or an endless felt which 
rotates in a copper trough containing a coating mixture 
which is usually maintained at a temperature of 120° Fahr. 

The amount of material put on to the surface of the 



144 



THE MANUFACTUEE OF PAPEE 



paper is varied by altering the proportion of water in the 
trough. As the wet coated paper is drawn over the drum 
it comes into contact with a number of flat brushes which 
move from side to side and brush the coating well into the 
paper. 

The last two or three brushes on the drum are made of 
very fine bristles, so that when the coated paper leaves the 
machine the surface is perfectly even and free from brush 
marks. The wet paper is then drawn up an inclined ladder 




Fig. 45. — Sectional Elevation of " Coating" Plant. 

by an ingenious device, which causes the paper to fall into 
festoons or loops, and these are carried bodily forward by 
means of travelling chains. The process, somewhat difficult 
to describe, is more easily understood by a study of the 
illustrations given. 

The paper is dried by a current of warm air which can 
be obtained by means of steam pipes placed below the 
festoons or with a special air blower. The dry paper is 
then led through guide rolls and wound uj) in the form of 
a reel. 

The paper at this stage has a dull coated surface, which 



SPECIAL KINDS OF PAPEE 145 

is somewhat rough and unfinished, and a high jDoHsh is 
imparted to it by a machine known as a supercalender. 

The supercalender consists of a number of alternate 
steel and cotton or paper rolls placed vertically in a stack 
one above the other. When the coated paper is led through 
this machine the friction of the alternate steel and cotton 
rolls produces a high finish on its surface. 

An art paper coated on both sides is manufactured by 
passiiig the paper through the coating machine twice. 
Machines have been devised for coating both sides of the 
paper at one operation, but these are not in very general 
use. 

Tinted art papers are prepared in the same manner, the 
desired colour being obtained by the addition of pigments 
or aniline dyes to the mixture in the trough containing the 
coating materials. When the two sides of such tinted papers 
are coloured differently, they are often described as duplex 
coated papers. 

Imitation Art Papers are prepared by quite a different 
process, although they have the appearance, more or less, 
of the coated paper. They are merely esparto papers very 
heavily loaded, containing frequently as much as 25 to 30 
per cent, of mineral matter prepared as follows : — 

Bleached esparto half-stuff is beaten together with any 
suitable proportion of chemical wood pulp in an ordinary 
beating engine, and a large quantity of china clay is added 
at the same time. The beating is carried out under condi- 
tions which favour the retention of as much china clay as 
the pulp will hold while being converted into paper on the 
Fourdrinier machine. 

After the paper passes over the drying cylinders of the 
machine it is passed through the calenders in the usual 
way, but the surface of the paper is damped by means of a 
fine water sjpray just before it enters the calender rolls. 

p. L 



146 . THE MANUEACTUEE OF PAPEE 

The result is that a " water-finish," so called, is imparted 
to the paper, and a close imitation of the genuine art paper 
is obtained, the effect of this peculiar treatment being to 
compress the fibres and bring the clay up, as it were, to the 
surface. 

A paper containing such a large proportion of mineral 
matter intimately mixed with the fibre is naturally very 
weak. It easily tears, and if moistened with water goes all 
to pieces. At the same time it is a cheap substitute for 
high-class art paper, being suitable for circulars, temporary 
catalogues, and similar printed matter. 

In an " art " paper the nature of the fibrous constituents 
is too often regarded as a matter of secondary importance, 
because in the process of printing the ink does not come 
into contact at all with the paper, and an impression is 
produced merely on a layer of clay which is bound together 
by the glue. 

The illustrations are not absolutely permanent, and it is 
perfectly easy to remove the whole of the impression and 
the coating itself by immersing a sheet of the paper in 
warm water and rubbing the surface gently with the fingers, 
or with a camel-hair brush. 

In fact the amount of coating matter which has been 
brushed on to a paper can be determined approximately by 
weighing a piece of the coated paper, removing the mineral 
matter and glue from both sides as indicated, allowing the 
paper to dry again, and then re-weighing, the loss in weight 
representing the amount of coating. 

It is not surprising to find that the true paper is merely 
regarded as a convenient means of producing, so to speak, 
a smooth surface of clay, and an examination of the 
material between the two clay surfaces often reveals a 
paper of very low quality. 

There are one or two empirical methods for testing the 



SPECIAL KINDS OP PAPER 147 

condition of coating on an art paper. If the coating is firm 
and adherent, then on pressing the moistened thumb on to 
the surface none of the coating matter is removed, but in 
a badly-made art paper some of the coating adheres to the 
thumb. 

Another method is to crumple a sheet of paper between 
the fingers, and if any of the coating comes away easily the 
paper is considered of poor quality. 

Tke complete examination of an art paper, apart from 
the practical test of printing, involves the determination of 
the amount of coating matter added to the paper, the pro- 
portion of glue in the coating, and the usual analysis of the 
paper itself. 

Packing Papers. 

This term may be applied to wrappings specially treated 
with substances which render the paper air and water proof. 
They are principally used for preserving food, or such 
articles as tobacco, which require to be kept slightly 
moist. 

Waxed Paper.— -The paper in the form of a continuous 
sheet is passed through a bath of melted wax at a high 
temperature, any excess being removed by squeezing rolls 
through which the hot waxed paper is passed. The paper 
is led over skeleton drums and thoroughly cooled before 
being cut into sheets. 

Butter Paper. — Ordinary parchment paper is generally 
used, but for special purposes a solution containing albumen 
and saltpetre is utilised for impregnating paper. 

Hardware Paper. — Needles and silver goods are fre- 
quently wrapi3ed in paper impregnated or mixed with 
substances which are supposed to prevent deleterious fumes 
from coming into contact with them. The use of black papers 

L 2 



148 THE MANUFACTUEE OF PAPEE 

heavily loaded with pigment, sized with glue and an excess 
of alum, is commonly resorted to. For silver ware, paper 
dipped in a solution of caustic soda containing zinc oxide 
is used. A recent patent suggests the impregnation of 
paper with heavy hydrocarbon oils, which being slightly 
volatile cover the goods, such as needles, with a thin 
film. 

Paraffin Paper. — Large quantities of this paper are con- 
sumed for packing food and other articles which need 
protection from air and moisture. 

The paper is either passed through a bath of paraffin 
or passed over a roller which rotates in a trough of 
paraffin. 

If the paper is to be coated on both sides it is passed 
through the bath containing the paraffin in a melted con- 
dition, the excess of which is scraped from the paper as it 
leaves the bath. The paper is cooled l)y exposure to air, 
and when the paraffin has solidified upon the sheet 
the paper is wound up on a roller at the end of the 
machine. 

If the paper is to be coated on one side only it is passed 
over a heated roller which revolves in a bath of melted 
paraffin, the other operations of drying and finishing 
being the same as in the case of a paper coated on both 
sides. 

Tinfoil Papers, required for packing tea, coffee, and 
similar foodstuffs, are prepared by coating cheap paper 
with a solution of gum and finely powdered tin. The 
manufacture of the fine powder is accomplished by melting 
tin at a low temperature and shaking it continually as it 
cools down, whereby a mixture of fine powder and large 
particles is produced, the latter being separated out by 
agitation of water. 

Tin in a fine state of division can also be obtained by a 



SPECIAL KINDS OF PAPER 149 

chemical process. Granulated tin is dissolved in strong 
hydrochloric acid, the solution diluted with water, and a 
stick of zinc introduced into the solution. The tin is 
gradually precipitated. 

The dried powder is coated on to the paper with gum, 
and when the paper is dry the necessary degree of brilliancy 
produced by suitable calendering. 

Transfer Papers. — A number of important operations 
reqffire the use of what are known as transfer papers, so 
that a design written or printed upon a specially prepared 
surface can be transferred to another surface from which 
duplicate copies may be obtained. The principle upon 
which all such operations are based is the coating of suit- 
able paper with starch, flour, and gum, singly or mixed, 
so as to give a surface firm enough to take the design, 
but which readily breaks up when the printed side is 
pressed against the wood, stone, or metal object intended 
to receive the design. 

Thus a paper may first be dusted over with dry starch, or 
coated with starch paste and then dried. A layer of dextrine 
may then be put over the starch coating, and the design 
printed upon the dextrine surface. When the paper is turned 
face downward on a sticky metal plate the design adheres 
to the metal, and the paper is easily pulled off, owing to 
the dry starch layer between it and the dextrine being non- 
adhesive. 

This principle is utilised in producing designs upon tins 
used for packing, metal advertisement plates, domestic 
articles of every kind, stoneware and earthenware 
goods. 

It is further applied in the preparation of lithographic 
stones required for printing. 

Each class of work demands paper of a suitable character, 
but the principle of an easily detached surface-coating is the 



150 THE MANUFACTUEE OF PAPEE 

same for all. The main difficulty experienced is the liability 
of paper to stretch when damped, and various methods are 
devised to obviate this, either by em^Dloying paper which 
stretches very little when damp, or by making the paper 
partially waterproof before use. 

Papier-mache. — This name indicates a preparation of 
paper or paper pulp mixed with various mineral sub- 
stances firmly cemented together by animal or vegetable 
adhesives. 

The paper pulp used for high-class goods consists of pure 
wood cellulose, while for the commoner qualities mechanical 
wood pulp, waste papers, and any similar fibrous material 
are employed. 

The mineral substances used are china clay, chalk, 
gypsum, barytes, ochre, sienna, and other mineral pig- 
ments. 

The adhesive materials are glue, casein, gum, starch, 
j)aste, dextrine, Iceland moss, or wax. 

For experimental purposes, small quantities of papier- 
mache may be prepared in the following manner : — 

When old newspapers or brown papers are used as the 
fibrous basis of the papier-mache, they are first torn up 
into small pieces, moistened with hot water, tied up in a 
small cloth bag or sack, which must only be half filled, 
and then immersed in a basin of warm water and thoroughly 
kneaded by hand, so that the paper is gradually reduced to 
the condition of pulp. If the kneading process is carried 
out thoroughly the paper is entirely reduced to pulp. 
The excess of water can be removed by pressure and 
the preparation of the final mixture completed by the 
incorporation of clay, pigment, and adhesive. 

In the preparation of papier-mache for goods on a large 
scale a beating engine is used in order to break up the old 
paper or wood pulp into a fibrous condition. 



SPECIAL KINDS OF PAPER 



151 



The following formulae can be used for making papier- 
mache : — 



(1) 


(2) 


(3) 


(4) 


Pulp . 


22 


Pulp 


. 22 


Pulp 


12 


Pulp . 


. 33 


Clay . 


37 


Chalk 


. 30 


Eosin size 


22 


Starch 


9 


Casein 


37 


Glue 


. 4 


Flour 


11 


Clay . 


. 9 


Water 


4 


Water 


. 44 


China clay 


11 


Water 


. 49 


- 








Water 


44 








100 




100 




100 




100 



Plaster Moulds. — Plaster of Paris or gypsum is the main 
article used for moulds and pattern. The preparation of 
gypsum for casting is made as follows : — The gypsum is 
gradually worked up into a creamy paste with water, the 
mixing being done quickly yet thoroughly. 

The pattern of which it is desired to form a mould must 
be coated with oil. Around the pattern placed on a table a 
wall of wood or pasteboard is fixed, so that a basin will be 
formed of suitable depth, preventing the gypsum from 
flowing away. Patterns of figures or of curved articles 
have to be made in two or more parts. For that purpose 
the pattern is usually cut into two pieces. Two moulds are 
now readily obtainable by first oiling the pattern and by 
pouring the gypsum in a thin state gradually over the 
surface, to avoid the forming of air bubbles. 

The rapid drying of the soaked gypsum is sometimes 
inconvenient, but the addition of a saturated solution of 
borax in water to the gypsum mixture can be resorted to as 
a check. 

Various means are employed for hardening and strength- 
ening the plaster cast, such as the addition of coarse paper 
fibres, shreds of canvas, iron filings, or wire, 



152 



THE MANUFACTUEE OF PAPEE 



Colouring. — Usually a cheap water colour only is required ; 
a light coating of a cheap varnish may be sufficient. 
In other cases a water colour serving as a filler for 
smoothing the surface may receive a finish of one or more 
coats of resinous solutions in alcohol or of copal varnish. 
Many goods are coated with asphaltum or Japan varnish 
and dried in cold or hot air. 

Some of the articles may be decorated with scrolls or 
arabesques in oil colours or enamels, or the lines may 
be covered with bronze powder, or with metal, gold, or 
aluminium leaf. 

Varnishing. — The following varnish recipes are suit- 
able : — 



(1) 



Shellac . 20 
Alcohol . 10 
Lamp black 10 



100 



(2) 



Shellac . 10 
Eosin . 10 

Alcohol . 60 
Lampblack 20 

100 



(3) 



Shellac . 6 

Sandarac . 3 

Mastic . 18 

Alcohol . 73 

100 



(4) 



Sandarac . 15 

Mastic . 5 

Turpentine . 5 

Alcohol . 75 

100 



CHAPTER VIII 

CHEMICALS USED IN PAPBE-MAKING 

T^ manufacture of paper is a highly technical industry, 
which requires a practical knowledge of mechanical engineer- 
ing, as well as an intimate acquaintance with the many 
important chemical problems connected with the art. 

The following brief description of the various chemicals 
used in the manufacture of paper is divided into certain 
classes, based upon the order of the operations through 
which the raw material passes before its final conversion 
into paper : — 

(1) The alkaline processes used for treating raw fibre : 
soda ash ; caustic soda ; lime ; recovered ash. 

(2) The conversion of wood into sulphite pulp : sulphur ; 
limestone. 

(3) The operation of bleaching : bleaching powder ; 
antichlors ; acids. 

(4) The sizing and loading of paper : casein ; gelatine ; 
rosin size ; alum ; starch ; silicate of soda ; pigments 
and soluble dyes ; mordants. 

Mineral substances for loading : clay, blanc fixe, etc. 

Carbonate of Soda. — This substance, also known under 
the trade names of alkali and soda ash, is used in the 
paper mill for the manufacture of caustic soda. It is 
purchased by the paper-maker from the chemical works, 
and used together with the recovered ash (see page 78) for 
the production of caustic soda solution, which is required 
in the treatment of raw fibres. 



154 



THE MANUFACTUEE OF PAPER 



It is also used for the preparation of rosin size (see 
" Eosin Size ") and in softening hard waters for steam -raising 

purposes. 

Sodium Carbonate Table. 

Showing percentage by weight and pounds per 100 gallons in 
solutions of various densities. 





Percentage by Weight. 


100 gallons contain pounds of 


Twaddell. 














NaaO. 


Naa COg. 


Naa O. 


Naa CO3. 


48 per cent. Ash. 


1 


0-28 


0-47 


2-76 


4-72 


5 


74 


2 


0-56 


0-95 


5 


61 


9-60 


11 


68 


3 


0-84 


1-42 


8 


42 


14-41 


17 


56 


4 


1-11 


1-90 


11 


34 


19-38 


23 


64 


5 


1-39 


2-38 


14 


26 


24-40 


29 


73 


6 


1-67 


2-85 


17 


10 


29-36 


35 


77 


7 


1-95 


3-33 


20 


16 


34-46 


42 


00 


8 


2-22 


3-80 


23 


12 


39-52 


48 


15 


9 


2-50 


4-28 


26 


17 


44-72 


54 


50 


10 


2-78 


4-76 


29 


71 


50-00 


60 


90 


11 


3-06 


5-23 


32 


27 


55-18 


67 


22 


12 


3-34 


5-71 


35 


36 


60-50 


73 


72 


13 


3-61 


6-17 


38 


43 


65-72 


'80 


07 


14 


3-88 


6-64 


41 


57 


71-06 


86 


58 


15 


4-16 


7-10 


44 


65 


76-33 


93 


03 


16 


4-42 


7-57 


47 


80 


81-77 


99 


61 


17 


4-70 


8-04 


51 


02 


87-24 


106 


31 


18 


4-97 


8-51 


54 


25 


92-74 


113 


10 


19 


5-24 


8-97 


57 


45 


98-26 


119 


70 


20 


5-52 


9-43 


60 


67 


103-70 


126 


42 


21 


5-79 


9-90 


63 


98 


109-40 


133 


45 


22 


6-06 


10-37 


67 


32 


115-10 


140 


12 


23 


6-33 


10-83 


70 


63 


120-81 


147 


10 


24 


661 


11-30 


74 


00 


126-62 


154 


20 


25 


6-88 


11-76 


77 


38 


132-30 


161 


12 


26 


7-15 


12-23 


80 


83 


13,s-20 


168 


51 


27 


7-42 


12-70 


84 


31 


144-12 


175 


70 


28 


7-70 


13-16 


87 


67 


150-20 


182 


70 


29 


7-97 


13-63 


91 


28 


156-15 


190 


14 


30 


8-24 


14-09 


94-77 


162-00 


197-40 



Analysis. — The value of soda ash, carbonate of soda, and 
recovered ash depends on the amount of available alkali 
(Nag 0) present. 



CHEMICALS USED IN PAPEE -MAKING 155 

A weighed quantity (15 '5 grammes conveniently) is 
dissolved in a measured volume of distilled water (500 c.c), 
and titrated with standard normal hydrochloric acid, methyl 
orange indicator being used. 

Caustic Soda. — Eaw vegetable fibres may be reduced to 
the condition of paper pulp by treatment with caustic soda. 
In practice this process is largely resorted to for the 
manufacture of pulp from esparto, straw, and wood, the 
spent"?;austic soda being recovered and used again; 

The paper-maker prepares the caustic required for digest- 
ing the raw material from recovered ash and carbonate 
of soda. 

Aconvenient volume of clear liquor obtained by lixiviating 
the recovered ash is boiled with lime in suitable causticising 
pans, the reaction being represented as follows : — 

Na2 CO3 + Ca + H2 = 2 Na OH + Ca CO3. 
Soda ash + Lime + Water = Caustic soda + Chalk. 

According to this equation, 100 lbs. of soda ash require 
53 lbs. of quicklime, but a slight excess is generally added, 
58 or 60 lbs. being the usual amount actually employed. 
Several precautions should be observed in the process of 
causticising. 

(1) The liquor from the recovered soda should be bright 
and clear, indicating complete incineration of the ash. 

(2) The liquor is best causticised at a density between 
1-050 and 1-100 (10— 20,Twaddell). With stronger solutions 
the reaction is complicated and the yield of caustic soda 
reduced. Lunge has shown that if the density of the 
solution is 1*025 the proportion of soda causticised is 
99'5 per cent., whereas at a density of 1*150 it is only 
94-5 per cent. In the latter case the caustic soda formed 
acts upon the chalk produced and is reconverted into 
carbonate. 



156 



THE MANUFACTURE OF PAPEE 



(3) The large quantities of chalk residue resulting from 
the reaction must be thoroughly and carefully washed. 
The economy of the whole process depends in no small 
measure upon this seemingly small detail. 

Caustic Soda Tables. 

Showing quantity of liquor obtained from 1 cwt. of caustic soda and 
the amount of caustic soda in 100 gallons of liquor (adapted from 
Lunffe and others) . 



Twaddell. 


Gallons obtained per hundred- 
weight of Caustic. 


Twaddell. 


Pounds of Caustic Soda per 
100 gallons Liquor. 


60 per cent. 
Caustic. 


77 per cent. 
Caustic Pure. 


60 per cent. 
Caustic. 


77 per cent. 
Caustic Pure. 


1 


1,777 


2,358 


1 


6-3 


4-75 


2 


896 


1,179 


2 


12-5 


9-5 


3 


596 


767 


3 


18-8 


14-6 


4 


448 


574 


4 


25-0 


19-5 


5 


359 


457 


5 


31-2 


24-5 


6 


298 


384 


6 


37-6 


29-2 


7 


256 


330 


7 


43-8 


34-0 


8 


223 


287 


8 


501 


39-0 


9 


199 


256 


9 


56-2 


43-7 


10 


178 


229 


10 


62-9 


48-9 


11 


162 


208 


11 


69-1 


53-7 


12 


148 


190 


12 


75-7 


58-7 


13 


136 


176 


13 


82-1 


63-7 


14 


126 


166 


14 


88-5 


67-5 


15 


117-5 


152 


15 


95 


73-5 


16 


110 


141-5 


16 


101-5 


79-0 


17 


103-5 


135 


17 


107-8 


83-0 


18 


98 


125-5 


18 


114-4 


89-0 


19 


92-8 


119-5 


19 


120-8 


93-8 


20 


88 


114 


20 


127-2 


98-0 


25 


70 


90-3 


25 


159-5 


124-0 


30 


56-5 


73 


30 


197-3 


153-0 


35 


48 


61-5 


35 


234-9 


182-2 


40 


41 


53 


40 


272-6 


211-6 


45 


35-3 


45-5 


45 


317-4 


246-3 


50 


31 


40 


50 


362-1 


2S1-0 



CHEMICALS USED IN PAPEE-MAIvING 



157 



Dilution Table for Strong Liquors. 

Showing number of gallons of water required to reduce the densit^^ 
of 100 gallons of liquor from a higher density, D, to a lower 
density, d. (See page 163). 



Ps- 






Lower Density, d. 








l^s 


















Pb 


14. 


13. 


12. 


11. 


10. 


9. 


8. 


7. 


6. 


5. 


4. 


42 


200 
185 


223 


250 


281-8 


320 


367 


425 


500 


600 


740 


9.50 


40 


207 


233-3 


263-6 


300 


344-4 


400 


471-4 


566-6 


700 


900 


38 


171 


192 


216-6 


245-5 


280 


322-2 


375 


442-8 


533-3 


660 


8.50 


36 


157 


177 


200 


227-3 


260 


300 


3.50 


414-3 


500 


620 


800 


34 


143 


161-5 


183-3 


209-1 


240 


277-7 


325 


385-7 


466-6 


580 


750 


32 


128-6 


146 


166-6 


191 


220 


255-5 


300 


357-1 


433-3 


540 


700 


30 


114-3 


130-6 


150 


172-8 


200 


233-3 


275 


328-5 


400 


500 


650 


28 


100 


115-3 


133-3 


154-6 


180 


211-1 


250 


300 


366-6 


460 


600 


26 


85-7 


100 


116-6 


136-4 


160 


188-8 


225 


271-4 


333-3 


420 


550 


24 


71-4 


84-6 


100 


118-2 


140 


166-6 


200 


243 


300 


380 


500 


22 


57-1 


69-2 


83-3 


100 


120 


144-4 


175 


214-4 


266-6 


340 


450 


20 


43 


53-6 


66-6 


81-8 


100 


122-2 


1.50 


185-7 


233-3 


300 


400 


18 


28-6 


38-4 


50 


63-7 


80 


100 


125 


157 


200 


260 


350 


16 


14-3 


23 


33-3 


45-5 


60 


77-7 


100 


128-5 


166-6 


220 


300 



Lime and Limestone. — Carbonate of soda and recovered 
ash are converted into caustic soda by means of lime. 
About sixty parts of lime are necessary for the conversion 
of 100 parts of carbonate of soda. Large quantities of 
insoluble carbonate of lime are produced in this opera- 
tion, and great care is necessary to prevent a loss of 
caustic soda which occurs if the residue is not thoroughly 
washed. In some cases the residual chalk is drained by 
vacuum filters in order to remove all traces of soluble 
alkali. Processes have been devised for calcining the 
residue so as to convert the carbonate into caustic lime 
to be used over again, but no economical and practical 
method has yet been found. The treatment of the residual 
chalk with sulphuric acid for the production of calcium 
sulphate appears feasible, but the substance obtained is 
very impure, and therefore has little commercial value. 



158 



THE MANUFAOTUEE OP PAPEE 



Limestone is required in considerable quantity for the 
preparation of sulphite of lime for the manufacture of 
wood pulp. 

Recovered Ash. — The black liquor obtained during the 
process of the boiling of straw, esparto, and other paper- 
making fibres contains a large proportion of non-fibrous 
organic constituents derived from the fibres, the quantity 
of which may be gauged from the fact that these fibres 
generally lose 50 per cent, of their weight when being 
boiled. The black liquor on evaporation yields a thick 
resinous mass, which is converted into carbonate of soda 
when burnt. 

Advantage is taken of this fact to carry out a process of 
incineration on a large scale, so that heat derived from the 
burning off of the resinous mass is utilised for evaporation 
of weaker liquors. The ash is drawn from special furnaces, 
put aside, and allowed to char quietly, so that the car- 
bonaceous matter is more or less completely burnt away. 
The ash in this form contains about 40 per cent, of soda, 
its composition being determined by the nature of the fibre 
which has been treated. In the case of straw, the amount 
of silicate is considerable, as shown by the following typical 
analysis : — 

Sodium carbonate . , . , . 70'2 



Sodium hydrate 

Sodium sulphate 

Sodium chloride 

Silica 

Oxides of iron and alumina 

Unburnt carbon, etc. . 



2-3 
4-1 
7-5 

7-5 

0-75 

7-65 



100-00 



At the present time there is no process in general use for 
the recovery of the Uquors used in the treatment of wood 



CHEMICALS USED IN PAPEE-MAKING 159 

by the sulphite process. Many schemes have been proposed, 
the most promising of which is that of Drewsen. 

Sulphur and Sulphites. — The pale yellow brittle substance 
known as sulphur is too familiar to require any detailed 
description. It unites with oxygen in various proportions, 
and these in contact with watei- form the various sulphur 
acids known to commerce. Sulphur burned with a limited 
quantity of air forms sulphurous acid gas, and this substance 
is the ehief product of oxidation, which by further treatment 
can be converted into sulphites. 

In the manufacture of the sulphur compounds required 
in the preparation of "wood pulp, the furnace for burning 
the sulphur consists of a flat-bottomed cast iron retort 
which is very shallow, and provided with a curved top, to 
which a pipe is fixed, so that the sulphurous acid may be 
conveyed away from the furnace. In the most recent form 
of sulphur oven a small conical-shaped revolving furnace 
is employed, which produces a satisfactory gas of constant 
composition very economically. 

Bisulphite of Lime. — This compound is obtained when 
the sulphurous acid gas is brought into contact with 
moistened limestone. In the manufacture of bisulphite of 
lime on a large scale the sulphurous acid gas is drawn or 
pumped up tall circular towers filled with blocks of lime- 
stone, kept moistened by a carefully regulated stream of 
water flowing from the top of the tower. 

In another system known as the acid tank process, the 
gas is forced into large circular vats containing milk of 
lime. 

In either case a solution is prepared containing bisulphite 
of lime, together with a certain proportion of free sulphurous 
acid, the object of the pulp manufacturer being to obtain a 
solution containing as large a proportion of free sulphurous 
acid as possible. The composition of a solution will vary 



160 THE MANUFACTUEE OF PAPER 

on this account, and the following may be quoted as being 
an example of such a liquor : — 

Free sulphurous acid . . 3'23 per cent. 
Combined sulphurous acid . 0*77 ,, ,, 

4-00 „ „ 



For experimental purposes the bisulphite of lime solution 
may be prepared by passing sulphurous acid gas into a 
mixture of water and sulphite of lime. The latter compound 
is insoluble in water, but gradually dissolves when the gas 
is absorbed. A known weight of sulphite of lime is added 
to a measured volume of water, and the sulphurous acid 
gas discharged into the mixture from a siphon of com- 
pressed sulphurous acid. The amount of gas absorbed is 
determined by weighing the siphon before and after use, 
the loss of weight representing the gas discharged. 
The following figures may be quoted as an example : — 

Quantities used. 

Calcium sulphite . . . 536 grammes. 

Water 7100 c.c. 

Gas absorbed .... 534 grammes. 

Density of solution . . .18° Twaddell. 

The composition of the solution prepared is — 

Combined sulphurous acid . . . 3'50 

Free sulphurous acid .... 6*54 

Lime 3-06 

Water 86-90 



100-00 



Analysis. — The examination of sulphite liquors for free 
and combined sulphurous acid is made by means of stan- 
dard iodine solution and normal caustic soda solution. 



CHEMICALS USED IN PAPEE-MAKING 



161 



A known volume of the sulphite liquor is first titrated 
with standard iodine solution, the number of cubic centi- 
metres required being a measure of the total sulphurous acid. 
Each cubic centimetre standard iodine solution = '0032 
grammes SO2. The titrated liquor is then treated with 
standard caustic soda in quantity sufficient to exactly 
neutralise the acid. The volume of caustic soda solu- 
tion used minus the number of cubic centimetres of iodine 
first *added is a measure of the free sulj^hurous acid. 

Bleacldng Powder. — This substance is prepared on a 
large scale by allowing chlorine gas to act upon dry 
slaked lime. The lime absorbs nearly one-half its weight 
of chlorine and forms a dry white jDowder, having a very 
pungent odour. The best bleaching powder contains about 
37 per cent, of what is termed "available chlorine." The 
substance, on being treated with water, gives a greenish- 
coloured solution known as bleach liquor, and when raw 
paper-uiaking material, after having been digested with 
caustic soda, is treated with this solution, it is gradually 
bleached to a white colour. The composition of the powder 
may be represented approximately as follows : — 

Available chlorine (combined with lime) . . 36*00 
Chlorine in the form of chloride . . 0-32 
Chlorine in the form of chlorate . . 0-26 
Lime ....... 44"66 

Magnesia 0*43 

Silica, iron oxides, etc 1"33 

Insoluble matter ..... 17'00 

100-00 

Since the amount of bleach used for wood pulps varies 
from 8 per cent, to 25 per cent, of powder on the dry wood 
pulp, the cost of bleaching in some cases is considerable. 
The economy of the process depends in some measure 

p. M 



162 



THE MANtJFACTUEE OF PAPER 



upon the care exercised in the purchase of bleaching powder 

of standard quaUty, the storage of same in a dark, cool 

place, and the efficient treatment or exhaustion of the 

powder when the bleach liquor is prepared. 

The powder is usually agitated for about an hour with 

water sufficient to produce a liquor of 13° — 15° Twaddell. 

The undissolved powder is allowed to settle and the clear 

solution siphoned off, after which the sediment is washed 

once or twice to remove all the soluble matter completely. 

Bleach Liquor Table. 

Showing for bleaching powder solutions of known density the quantity 
of powder necessary to produce 100 gallons of liquor and the 
number of gallons obtained from 1 cwt. of powder (adapted from 
Lunge and Beichofen). 





Available 


Number of Gallons obtained 
from 112 lbs. of Powder. 


Pounds of Powder per 100 
gallons of Liquor. 




Chlorine. 
Pounds per 
100 gallons. 










Twaddell. 


34 per cent. 
Powder. 


35 per cent. 
Powder. 


34 per cent. 
Powder. 


35 per cent. 
Powder. 


0-25 


0-70 


5,464 


5,600 


2-05 


2-00 


o-.^o 


1-40 


2,725 


2,800 


4-11 


4-00 


1 
2 


2-71 

5-58 


1,405 
681 


1,445 

702 


7-97 
16-41 


7-74 
15-94 


3 


8-J8 


4^8 


462 


24-95 


24-23 


4 


11-41 


334 


340 


33-55 


32-60 


o 


14-17 


264 


270 


42-58 


41-34 


6 


17-36 


219-5 


225 


51-06 


49-60 


7 


20--I4 


186 


191 


60-11 


58-40 


8 


?3-75 


160 


165 


69-85 


67-85 


9 


26-62 


141 


147 


78-30 


76-57 


10 


29-60 


V29 


132-5 


87-06 


84-54 


11 


32-68 


116-5 


120 


96-11 


93-37 


12 


35-81 


106-5 


109-5 


105-32 


102-31 


13 


39-10 


98 


100 


115-00 


111-70 


14 


42-31 


90 


92-5 


124-45 


12090 


15 


45'70 


84 


86 


134-41 


130-56 


16 


48-96 


78 


80 


143-80 


139-71 


17 


52-27 


73'5 


75 


153-53 


149-34 


18 


55-18 


69 


71 


162-30 


157-65 


19 


58-40 


655 


67 


171-00 


166-86 


20 


61-50 


61-5 


64 


180-88 


175-71 



CHEMICALS USED IN PAPER-MAKING 



163 



The best method for extracting powder is to agitate the 
material with water for a short period, and to stop the 
mixing process directly the maximum density has been 
obtained, which usually takes place in 15 minutes. Pro- 
longed agitating prevents the powder from settling readily. 

The maximum quantities of liquor which can be obtained 
from bleaching powder are shown on page 162. The 
following table is useful as showing the amount of water 
reqitfred for diluting strong liquors, the figures being 
applicable to any solution independent of the nature of 
the dissolved substance. 



Dilution Table foe Weak Liquors. 

Showing number of gallons of water required to reduce the density 
of 100 gallons of liquor from a higlier densitj-, D, to a lower 
density, d. (See page 157.) 







Lower Density, d. 








12. 


11. 


10. 


9. 


8. 


7. 


6. 


0. 


4. 


3. 


2. 


1. 


16 


33-3 


45-4 


60 


77-7 


100 


128-5 


166-6 


220 


300 


433-3 


700 


1,500 


15 


25-0 


36-4 


50 


66-6 


87-5 


114-3 


150 


200 


275 


400 


650 


1,400 


14 


1(5-6 27-3 


40 


55"5 


75 


100 


133-3 


180 


250 


366-6 


600 


1,300 


13 


8-3 ■ H-2 


30 


44-4 


62-5 


85-7 


116-6 


160 


225 


333-3 


550 


1.200 


12 


9-1 


20 


33-3 


50 


71-4 


100 


140 


200 


300 


500 


1,100 


11 






10 


22-2 


37-5 


57- r 


83-3 


120 


175 


266-6 


450 


1,000 


10 








IM 


25 


42-8 


66-6 


100 


150 


233-3 


400 


900 


9 






12-5 


28-5 


50 


80 


125 


200 


350 


800 


8 












14-2 


33-3 


60 


100 


166-6 


300 


700 


7 














16-6 


40 


75 


133-3 


250 


600 


6 
















20 


50 


100 


200 


500 


5 


















25 


66-6 


150 


400 


4 




















33-3 


100 


300 



Antichlors. — The residues of chlorine which may be left 
in pulp after bleaching are frequently neutralised by the 
use of substances termed antichlors, which react with the 
calcium hypochlorite, converting it into chlorides. 

The sodium hyposulphite is the most frequently used 

M 2 



164 



THE MANUFAOTUEE OF PAPEE 



antichlor, the reaction between this and hypochlorite 
resulting in the formation of calcium sulphate and sodium 
chloride ; 100 lbs. of commercial bleaching powder will 
require 30 lbs. of crystallised sodium hyposulphite. 

The sulphites of soda and lime also act as antichlors, 
reducing the hypochlorite of calcium into sulpbate of lime 
or soda. The chief advantage of the use of sulphites is to 
be found in the fact that the substances obtained by the 
reaction are neutral. 

The best practice in bleaching is to avoid the necessity 
for using any forms of antichlors by careful regulation of the 
bleaching process. It has already been suggested in previous 
references to bleaching that the desired results are obtained 
when the pulp and bleach are left in contact with one 
another in tanks or drainers until the bleach is completely 
exhausted, the residual salts in solution being removed by 
thorough washing. 

Gelatine. — For animal- sized or tub-sized papers gelatine 
is used. It can be prepared by the paper-maker from hide 
clippings, sheep skins, bone, etc., or can be purchased 
ready made. 

Beadle gives the following interesting details as to the 
amount of gelatine which can be obtained from wet hide 
pieces : — 

Weight op Wet Hide Pieces, 2,128 lbs. 



Draught. 


Gallons. 


Per cent. 

Gelatine in 

Solution. 


Weight of 

Gelatine. 

Lbs. 


1 

2 

3 and 4 mixed 


126-48 
128-96 
135-20 


6-775 
6-052 
9-446 


85-64 

78-04 

127-63 


Total .. 


390-64 


291-31 



Percentage of gelatine on weight of wet skins = 13'69. 



CHEMICALS USED IN PAPEE-MAE:ING 



165 



A similar trial on the same class of wet hide pieces gave 
a yield of 13"23 per cent. 

Two trials, of a somewhat different class of wet hide 
pieces, gave respectively 13-11 and 12'8 per cent. 

The temperature of the draught water should be approxi- 
mately as follows : — - 



Draught. 


At Beginning. 


At End. 


1 

2 

3 and 4 


120° F. 
130° F. 
140° F. 


150° F. 
160° F. 
180° F. 



In the final draught it is often necessary to use live 
steam at the finish, but this should be avoided if possible. 

The water contained in wet hide pieces varies from 77 to 
90 per cent, in the different pieces, but in the bulk the 
average may be taken at 85 per cent. 

Casein. — Casein is the nitrogenous principle of milk, and 
belongs to the class of proteids which are definite com- 
pounds of oxygen, hydrogen, carbon, and nitrogen, forming 
the basis of the most important constituents of all animal 
fibres, albumen, casein, and gluten. A very pure form 
of casein is cheese made from skimmed milk. Casein 
belongs to that class of albumens which are soluble in 
water, e.g., egg albumen, blood albumen or serum, and 
lactalbumen, or milk albumen ; these are mostly precipi- 
tated from solution by , saturation with sodium chloride 
(common salt) or magnesium sulphate ; but they are all 
coagulated by heat. 

By the action of rennet on milk the proteid or albumen 
principle is converted into a curd (casein). This curd, 
when freed from fats, is insoluble in water, but is soluble 
in dilute acids, or alkalies, or alkaline carbonates, from 



166 THE MANUFACTURE OF PAPER 

which substances, however, it is reprecipitated by acidula- 
tion. Instead of the above method, casein may be pre- 
cipitated from milk by saturation with sulphate of magnesia, 
and washing the precipitate with a solution of that salt 
until the washings contain no albumen, and then redissolv- 
ing the prepared casein by adding water. The salt still 
adhering to the precipitate enables it to dissolve. On a 
large scale the casein is usually prepared by treating the 
milk with acid. 

Casein is readily dissolved by alkalies and alkaline 
carbonates, borax, boracic acid solution, caustic soda, and 
bicarbonate of soda. 

Starch. — This substance is used in many classes of paper 
for improving the surface and finish. It is added to the 
pulp in the beating engine in the dry form as powder, or 
in the form of starch paste, produced by boiling the starch 
in water. 

The viscosity of the starch paste is somewhat increased 
by the addition of a small quantity of alkali, but due care 
must be exercised in boiling, which should only be carried 
out sufficiently to cause the starch granules to burst, as 
any excessive boiling causes the starch paste to lose some 
of its viscosity. 

The presence of starch in paper is detected by the blue 
coloration produced when the paper is dipped in.o a weak 
solution of iodine. The determination of the exact per- 
centage of starch in a paper is a matter of some difficulty. 

Silicate of Soda. — The precipitation of gelatinous silica 
upon the pulp in the beating engine is generally regarded 
as favourable to the production of a sheet of paper having 
what is known as a harder finish. The precipitation is 
effected by adding a solution of silicate of soda to the beat- 
ing engine, with the subsequent addition of sufficient 
sulphate of alumina to react with the silicate of soda. 



CHEMICALS USED IN PAPER-MAKING 



167 



Analysis of Commercial Alums. 
(Griffin and Little.) 



- 


(1) 


(2) 


(3) 


(4) 


Insoluble in water 
Alumina (AI2 Os) . 
Iron protoxide (Pe 0) . 
Iron sesquioxide (Fe2 0^) 
Zinc oxide (Zn 0) . 
Sod»(Na.2 0) 
Magnesia (Mg 0) . 
Sulphuric acid (SO3) combined 
Sulphuric acid (SO3) free 
Water by difference 




005 

15-47 

02 

000 

1-72 

37-26 

45-48 


10-61 

14-96 

0-13 

1-08 

0-57 

37-36 

1-08 

34-21 


0-11 

11-64 

0-06 

1-17 

4-75 
0-45 

35-98 
5-13 

40-71 


0-56 
16-58 

0-04 

0-56 

39-17 

43-09 




100-00 


100-00 


100-00 


10000 


Sizing test (parts of dry neutral 
rosin size precipitated by one 
part of the alum) 


3-32 


3-47 


3-19 


3-71 



Table showing Value of Solutions of Aluminium Sulphate. 





Pounds per 100 gallons. 


'a; 

1 


Pounds per 100 gallons. 


1 


AI2 O3. 


SOs. 


Sulphate of 

Alumina 

containing 15 per 

cent. AI2 O3. 


AI2 O3. 


SO3. 


Sulphate of 

Alumina 

containing 15 per 

cent. AI2 Os. 


1 


1-4 


3-3 


9-0 


14 


20-3 


47-3 


135-0 


2 


2-8 


6-5 


19-0 


16 


2:M 


53-8 


155-0 


3 


4-2 


9-8 


28-0 


18 


26-2 


60-3 


172-0 


4 


5-6 


13-0 


37-0 


20 


29-4 


68-5 


196-0 


5 


7-0 


16-3 


47-0 


25 


37-1 


86-5 


247-0 


6 


8-4 


19-6 


56-0 


30 


44-8 


104-4 


299-0 


7 


9-8 


22-8 


65-0 


35 


53-2 


124-0 


355-0 


8 


11-2 


26-1 


75-0 


40 


60-9 


142-0 


405-0 


9 


12-6 


29-4 


84-0 


45 


68-6 


159-9 


456-0 


10 


14-0 


32-6 


93-0 


50 


77-7 


181-0 


578-0 


11 


15-4 


35-9 


103-0 


55 


86-1 


200-6 


575-0 


12 


16-8 


39-1 


112-0 


60 


95-2 


221-8 


635-0 



168 THE MANUFAOTUEE OF PAPER 

Alum.— Alum, is one of the most important substances 
required in the manufacture of paper, its chief function 
relating to the sizing of paper. Various forms are utiKsed 
for this purpose, the purest being sulphate of alumina, 
required for high grade papers, and the cheaper form 
kno^A'n as alum cake, for news and common printing. 

The alum is manufactured on a large scale by heating 
cliina clay or bauxite with sulphuric acid. This reaction 
gives sulphate of alumina together with silica. If the mass 
is heated to dryness, it is sold under the name of alum cake. 
If the mass is extracted with hot water and the insoluble 
silica filtered off, the solution can be evaporated down for 
the production of sulphate of alumina, which is sold in the 
form of large cakes or in the form of crystals. 

By careful selection of raw material a sulphate of 
alumina can be prepared almost entirely free from iron. 
The presence of the latter is undesirable, since on exposure 
to air the sulphate of iron produced during the manufacture 
of the alum is slowly oxidised and turns brown. Ultimately 
this affects the colour of the finished paper. 

Alum is added to solutions of animal size or gelatine in 
order to thicken the solution and render it more viscous. 
It also acts as a preservative, and is used for regulating the 
absorption of the gelatine by the paper, the penetration 
effects being materially varied by the extent to which the 
alum is utilised. 

In the process of engine sizing, a term applied to the 
application of rosin size on account of the fact that the 
process is completed in the beating engine, alum plays an 
important part. The mere addition of the prepared rosin 
soap to the mixture of pulp and water in the beating engine 
does not size the paper, but the alum precipitates the rosin 
from its solution, producing a complex mixture said to 
consist of resinate of alumina and free rosin particles, and 



CHEMICALS USED IN PAPBE-MAKING 169 

subsequently the heat of the paper machine drying cylin- 
ders renders the paper more or less impermeable to 
moisture. 

The ajDpearance and tone of paper, more particularly of 
coloured papers, are brightened by the use of an excess of 
alum over and above that necessary to precipitate the rosin 
soap. 

Eosin Size. — This substance is used chiefly for the sizing 
of n^s and cheap printing papers, and is also employed 
together with gelatine for the commoner writing jDapers. 
It is prepared by boiling rosin with carbonate of soda 
under various conditions. 

Eosin, sometimes called colophony, is obtained from the 
sap of certain firs and pine trees. This on distillation 
yields spirits of turpentine, leaving behind as a residue the 
mixture of substances to which is given the name rosin. 
It behaves as an acid, and therefore will combine with 
certain alkaline oxides, producing soluble resinates. 

The nature of the rosin soap used in the paper mill 
varies according to the conditions under which the size is 
prepared. If a large proportion of rosin is used, then the 
size obtained consists of a mixture of resinate of soda 
together with free rosin dissolved in the solution. If the 
proportion of rosin is small compared with the amount of 
carbonate of soda, the composition of the final mixture is 
quite different. The difference in treatment results in the 
formation of — 

{A) Neutral Size, prepared by boiling a known weight of 
rosin with sufficient alkali to combine with it and form a 
neutral resinate of soda. Theoretically this may be obtained 
by using 630 parts of rosin to 100 parts of soda ash. It is 
doubtful how far the reaction is completed so as to produce 
an exactly neutral solution containing only resinate of 
soda. 



170 THE MANUFACTUEE OF PAPER 

{B) Acid Size. — When the proportion of rosin is largely 
increased the soda becomes converted into the alkaline 
resinate, and the excess of rosin is gradually dissolved in 
the resinate formed. 

The practical operations necessary for the preparation of 
the size are comparatively simple. In the case of size 
containing relatively small percentages of free rosin, the 
boiling is conducted in open vessels, but for the manufac- 
ture of rosin size containing large proportions of free rosin 
boiling under pressure in closed vessels must be resorted to. 

With the open pan process a steam jacketed pan is used, 
and the required quantity of alkali, dissolved in water, is 
placed therein and heated to boiling point. The rosin well 
powdered is added in small quantities from time to time, 
this being effected cautiously in order that the carbonic 
acid gas set free during the process may readily escape. 
The rosin is generally completely saponified after four 
or five hours' boiling. It is then passed through strainers 
into store tanks, from which it is drawn into the beating 
engines as required. 

In the case of rosin boiled under pressure a cylindrical 
vessel provided with a manhole at the top is used. The 
correct amounts of alkali and water are put into the digester, 
and also the rosin in a powdered form, the digester being 
fitted with a perforated plate placed about two feet above 
the bottom of the vessel in order to prevent the rosin 
forming into a hard mass at the bottom of the digester. 

It is possible in tbis way to manufacture a thick size 
containing 30 or 40 per cent, of free rosin and a compara- 
tively small proportion of water. Many paper mill firms 
prefer to purchase such size ready made. 

The most recent modification of the ordinary rosin size 
is a compound prepared by treating rosin with silicate of 
soda. This alkali dissolves rosin readily, and the soap 



CHEMICALS USED IN PAPEE-MAKING 171 

obtained when suitably diluted with water decomposes in 
the beating engine on the addition of aluminium sulphate, 
with the precipitation of a gelatinous silica which assists in 
hardening the paper. 

Bacon has patented a process in which powdered rosin 
is melted down with dry crystalline silicate of soda. The 
resultant product is ground to a fine powder, which is then 
ready for use. It dissolves easily in water, and when 
decomposed with the proper proportion of alum gives a 
gelatinous viscous mass said to have excellent sizing 
properties. 

The advantages of a dry powdered rosin size readily 
soluble in water are obvious. 

Loading. — The term "loading" is applied to the various 
substances which are employed for the purpose, as it 
is commonly supposed, of making paper heavy. But 
china clay and similar materials are not added simply 
in order to give weight to the paper, since they serve to 
produce opacity and to improve the surface of papers 
which could not be satisfactorily made unless such materials 
were used. 

Examination of Paper for Loading. — If a piece of paper is 
crumpled up, placed in a small crucible, and then ignited 
until all the carbonaceous matter has been burnt off, a 
residue is left in the crucible which may be white or 
coloured. This is usually termed the asli of the paper. 
The amount of ash present is determined by taking a 
weighed quantity of pajper and weighing the residue 
obtained. Special appliances can be obtained for making 
rapid determinations of the ash in paper, but for occasional 
analyses they are not required. 

China Clay. — This is the best known and most commonly 
used loading. The purest form of this material is kaolin, 
a natural substance formed by the gradual decomposition 



172 THE MANUFACTUEE OF PAPEE 

of felspatliic rocks arising from exposure to the long- 
continued action of air and water. The clay occurs in 
great abundance in Dorset, Cornwall, and Devon, the 
southern counties in England, where the most famous 
deposits are found. 

The natural mineral is levigated with water, and the 
mixture allowed to flow through a series of settling ponds, so 
that the clay gradually settles in the form of a fine deposit. 
The clay is dried and packed in bags. Its value is controlled 
largely by the purity of its colour and its freedom from grit 
and sand. It is essentially a silicate of alumina, having 
the approximate composition — 

Silica (Si O2) . • . • 43-00 

Alumina (AI2 O3) ... 35-00 

Combined water .... 10-00 

Moisture and impurities . . 12'00 



100-00 



The specific gravity of the dry substance is 2-50. 

It is utilised as a loading in all kinds of paper, and forms 
also the main ingredient in the coating found on ordinary 
art and chromo papers. 

Asli containing China Clay. — In news, cheap printings, 
and common art papers the ash almost invariably contains 
china clay. This substance is insoluble in dilute acids, but 
is acted upon by concentrated sulphuric acid when digested 
for some time. A simple test for the presence of china 
clay in ash is the blue coloration which is obtained when 
the ash after being ignited is gradually heated with a few 
drops of solution of cobalt nitrate. China clay can be 
decomposed by fusion with carbonate of soda in a crucible. 
By this means silicate of alumina is decomposed, and the 
alumina goes into solution, the silica remaining as an 



CHEMICALS USED IN PAPEE-MAKING 173 

insoluble residue. The filtered solution is boiled with an 
excess of ammonia which gives a gelatinous precipitate of 
aluminium hydrate. 

Sulphate of Lime. — This compound is valued chiefly for 
its brilliancy of colour, being used in high-class papers. It 
is slightly soluble in water, to the extent of about 23 lbs. in 
1,000 gallons, and this fact must be taken into account 
when the material is added to the pulp in the beating 
engine. 

It occurs naturally in a variety of forms, such as gypsum, 
alabaster, selenite, the first of which when finely powdered 
is sold to the paper-maker as gypsum, powdered plaster, and 
under other fancy names. 

It can be prepared artificially by adding sulphuric acid to 
solutions of calcium salts; and the precipitated product so 
obtained is sold as terra alba, pearl hardening, satinite, 
mineral white, etc. 

The tests for sulphate of lime in paper ash are based upon 
the following reactions : — 

Calcium sulphate is soluble in dilute hydrochloric acid. 
The addition of a few drops of barium chloride to the 
solution produces a dense heavy precipitate, indicating the 
sulphate. A small quantity of ammonium oxalate solution 
added to another portion of the dissolved calcium salt pre- 
viously neutralised with ammonia produces a precipitate 
and indicates calcium. 

A microscopic test of paper for the presence of sulphate 
of lime is based upon the slight solubility of the salt in 
water. The paper is boiled with some distilled water. The 
water is evaporated to a small bulk and transferred to a 
glass slip, and the gradual formation of characteristic 
sulphate of lime crystals can be seen by means of the 
microscope as the water cools down. 

French Chalk.' — This material is prepared by grinding 



174 



THE MANUFAGTUEE OF PAPEE 



talc into a fine powder, and possesses a good colour and a 
somewhat soapy feel. It is a silicate of magnesia, having 
the approximate composition — 



Silica (Si O2) . 

Magnesia (Mg 0) 

Water 

Traces of oxides, etc. 



62-00 

33-00 

4-30 

0-70 

100-00 



Other siHcates of magnesia used for paper-making are 
agalite and asbestine, the latter being a finely ground 
asbestos. 

The composition of asbestos is approximately — 



- 


Italian. 


Canadian. 


Lime and magnesia 

Silica ...... 

Oxides of iron and alumina . 

Total water 

Traces of soda, etc. 


38-0 
42-0 

50 
130 

2-0 


33-0 
41-0 
12-0 
12-0 
3-0 




100-00 


100-00 



CHAPTER IX 

THE PKOCBSS OF BEATING 

Intmduction. — The process of beating has for its object 
the complete breaking down of the bleached pulp to the 
condition of single fibres, and the further reduction of the 
fibres, when necessarj^ into smaller pieces. The disinte- 
gration of the material is essential for the production of 
a close even sheet of paper, and the amount of beating 
required varies greatly according to the nature of the raw 
material, and the class of paper to be produced. 

The textile trade, on the other hand, depends on a raw 
material composed of strong fibres, or of filaments cha- 
racterised by great length, and any processes of treatment 
which tend to reduce the length of such fibres are carefully 
avoided, and it is therefore obvious that fibres which are of 
no value for textile purposes can be approjDriated for paper- 
making. 

Condition of Fibres. — The great differences in the physical 
characteristics and structure of the fibres employed for 
paper-making suggest that the possible variations in the 
final product obtained by beating are very numerous. This 
is a well-known fact, and it is further to be noted that this 
mechanical operation brings about not merely alterations 
of a physical order, but introduces some interesting and 
important chemical changes. 

Of the better-known materials linen, with an average 
fibre length of 28 mm., the structure of which lends itself 
to considerable alteration by beating, is in marked contrast 



176 THE MANtJFACTURE OF PAPEE 

to esparto, the fibre length of which is only 1"5 mm. If 
the process of beating a linen rag merely resulted in the 
cutting of all the fibres of 28 mm. long into short fragments 
of 1'5 mm., there would be nothing remarkable in it, but 
the changes which occur in reducing the long linen fibre to 
1*5 or 2*0 mm. are of a far more important character than 
this. 

Early Methods. — In the early days of paper-making the 
disintegration of the half-stuff was effected by a true 
"beating" process, the rags being subjected to the action 
of heavy stampers, which broke up the mass of tangled 
fibre into a uniform pulp. The fibres for the most ]Dart 
retained their maximum length in this operation, which 
was exceedingly slow and tedious, though at the same time 
giving a sheet of paper of remarkable strength. 

The nearest imitation of these old-time rag papers is to 
be seen in the well-known Japanese papers, which are 
extraordinarily strong. Some of these the writer has 
examined in order to determine the length of the fibre. 
The sheets when held up to the light appear "cloudy" and 
" wild " owing to the presence of the long fibres, which have 
only been separated or teased out by the primitive methods 
of beating used, and not completely disintegrated. 

Conditions of Beating. — About a.d. 1700 there began a 
great epoch in the history of paper-making. With the 
invention of the Hollander engine about a.d. 1670, the pro- 
cess of disintegration was greatly hastened, because it was 
possible to reduce the half-stuff much more readily. The 
substitution of the idea of plain "beating" by a principle 
which combined the gradual isolation of the individual 
fibres with a splitting up of those fibres lengthwise and 
crosswise was not only an advantage in point of economy 
of time and cost, but also a material advance in the possi- 
bilities of greater variations in the finished paper. 



THE PROCESS OF BEATING 177 

The conditions of the process of beating carried out with 
a Hollander permit of considerable alteration, so that these 
changes in the fibre are not surprising when properly under- 
stood. In fact, it is now conceded that a close study of the 
theory and practice of beating is likely to bring about still 
more remarkable improvements in this important depart- 
ment of the paper-maker's work. The quality and character 
of the paper made may be varied with — 

(IV The origin of the raw material, e.g., rags, esparto, or 
wood ; 

(2) The condition of the material, e.g., old or new rags, 
green or mature esparto, mechanical or chemical wood pulp ; 

(3) The time occupied in beating, e.g., four hours for 
an ordinary rag printing and twelve hours for a rag parch- 
ment ; 

(4) The state of the beater knives, e.g., sharp tackle for 
blottings and dull tackle for cartridge papers ; 

(5) The speed of the beater roll, also its weight ; 

(6) The rate at which the beater roll is lowered on to the 
bedplate ; 

(7) The temperature of the contents of the engine. 

The Beater Roll. — If the beater roll is fitted with sharp 
knives, and this is put down close to the bedplate quickly, 
the fibres are cut up short, and they do not assimilate the 
water. If the roll is fitted with dull knives, or " tackle," as it 
is sometimes called, and it is lowered gradually, the fibres 
are drawn and bruised out without being greatly shortened. 
In this condition the stuff becomes very "wet," or "greasy," 
as it is termed. The cellulose enters into association with 
water when beaten for many hours, and the j)ulp in the 
beating engine changes into a curious greasy-like mass of 
a semi-transparent character. Eag pulp beaten for a long 
time produces a hard, translucent, dense sheet of paper. 
Flax thread beaten 48 to 60 hours is used in practice 

p. N 



178 THE MANUFACTUEE OF PAPEE 

for the manufacture of gramophone horns and similar 
purposes. 

Soft porous j)apers Hke blottings, filtering papers, heavy 
chromos, litho papers, antiques, light printings, are made 
from pulps which are beaten quickly with the roll put down 
close to the bedplate soon after the stuff has been filled in. 

With strong, dense, hard papers, such as parchments, 
banks, greaseproofs and the like, the pulp is beaten slowly 
and the roll lowered gradually. 

The nature of the pulp and the time occupied in beating 
are also important factors in producing these different 
papers, three to four hours being ample for an ordinary 
wood pulp printing, whereas a wood pulp parchment 
requires seven to eight hours. 

Beating Pulps Separately. — The use of esparto and wood 
pulp in conjunction with one another, or blended with rag, 
has introduced new problems into the question of beating. 
Perhaps the most important of these is the advisability of 
beating the pulps separately and eventually passing them 
through a mixer of some kind before discharging into a 
stuff chest. The necessity for differentiating the amount of 
beating is already partly recognised when very dissimilar 
pulps, such as strong rag and esparto, are blended, but the 
whole subject ought to be carefully studied by the paper- 
maker and investigated on its merits from the standpoint 
of " beating effects," apart from questions of cost and 
expediency. The former fully understood and exhaustively 
examined by practical tests would of course only be de- 
veloped if proved to be advantageous. 

The field of research in this direction has not yet been 
seriously explored. With the enormous consumption of 
wood pulps of varying quality made from many different 
species of wood by several processes, there is ample room 
for interesting and profitable enquiry, particularly as the 



THE PEOOESS OF BEATING 



179 



types of beating engine are so numerous. The effects 
produced by the Hollander, the refiner, the edge runner, 
the stone beater roll, and other mechanisms, are all of 
varying kinds. 

Effect of Peolonged Beating. 

The importance of a knowledge of the precise effects pro- 
duced by the beating of pulp cannot be emphasised too 




U 



V 




EiG. 46. — Cotton Pulp beaten 8 hours. 

much, and any contributions to the subject along the lines 
of special research will be welcomed by all students of 
cellulose. 

Some experiments were conducted by the writer in 1906 
with cotton rags, in order to determine the results obtained 

N 2 



180 THE MANUEACTUEE OE PAPEE 

by beating the pulp for a prolonged period under exact and 
specific conditions. 

The cotton rags, of good quality, were boiled with caustic 
soda in the usual way for six or seven hours, at a pressure 
of 15 to 20 lbs., washed and partially broken down in the rag 




EiG. 47. — Cotton Pulp beaten 37 liours. 

breaker, and finally bleached, made into half-stuff, and then 
transferred to a Hollander beating engine. 

The particular conditions specified for the beating opera- 
tion were that the beaterman should manipulate the pulp 
according to his usual routine for the manufacture of the 
paper which he was accustomed to make from these rags. 
In this case the routine process meant beating for eight 
hours, by which time the pulp was ready for the paper 
machine. In the ordinary course the pulp would be 



THE PROCESS OF BEATING 



181 



discharged into the stuff chest, and converted into a strong, 
thin, bank paper. 

During the prolonged beating the pulp became very soft 
and " greasy," and when made up into sheets the paper as 
it dried exhibited rtoiarkable differences in shrinkage, the 
dry sheets obtained from pulp beaten thirty-seven hours 
being much smaller than those obtained from pulp beaten 
only four or six hours. The actual shrinkage is shown in 
the following table : — 



Hours. 


Area of Sheet. 


Loss of Area. 


Relative 
Areas. 


Shrinkage 




Sq. mm. 


Sq. mm. 


Deckle 100 


per cent. 





26,384-0 


_ 


100-0 




4 


26,076-0 


308-0 


98-9 


1-1 


6 


25,520-1 


863-9 


96-7 


3-3 


8 


25,160-0 


1,224-0 


95-4 


4-6 


10 


24,794-8 


1,589-2 


93-9 


6-1 


13 


24,467-4 


1,916-6 


92-8 


7-2 


15 


24,215-2 


2,168-8 


91-8 


8-2 


17 


24,024-0 


2,360-0 


90-9 


9-1 


19 


23,616-2 


2,767-8 


89-6 


10-4 


21 


23,616-0 


2.768-0 


89-6 


10-4 


23 


23,535-7 


2,848-3 


89-3 


10-7 


25 


23,329-9 


3,054-1 


88-5 


11-5 


27 


22,920-5 


3,463-5 


86-9 


13-1 


29 


22,831-2 


3,552-8 


86-5 


13-5 


31 


22,492-9 


3,891-1 


85-3 


14-7 


33 


21,917-2 


4,466-8 


831 


16-9 


35 


21,226-1 


5,157-9 


80-5 


19-5 


37 


20,778-8 


5,605-2 


78-8 


21-2 



If these results are plotted in the form of a curve the 
relation between the period of beating and the shrinkage 
in area is clearly shown. For the first twenty hours 
the shrinkage is proportional to the period of beating, 
after which the curve assumes an irregular shape, show- 
ing a tendency for shrinkage to proceed at a faster 
rate. 



182 



THE MANUFACTUEE OF PAPER 



Weight and Substance of the Paper. — The shrinkage of 
the paper after prolonged beating indicates a closer and 
denser sheet, so that for papers of equal thickness the 
weight per unit area was much greater in the case of the 
pulp beaten for the full period. The results obtained are 
very interesting, and the following summary for a few of 
the readings obtained will serve to show the alteration 
effected. 



Weight of Thickness of 
Hours. [ 20,000 sq. mm.] Sheet, 
(jiams. mm. 



Gr;nn,s per 
sq. metre. 



Lbs. per ream 
480 sheets, 
20" X 30". 



Class A 
8-10 In-s. 

Class B 
19-21 hi'8. 

Class C 
33-35 lirs. 



1-875 
2-043 
2-203 



■183 



•189 



189 



93-75 



102-15 



110-15 



38-23 



41-05 



44-93 



Sizing and Glazing Effects. — The behaviour of the water- 
leaf paper after sizing and glazing gave some interesting 
results. In the first place, the effect of the altered density 
of the paper is strikingly shown by the amount of the size 
absorbed. Certain selected sheets were passed through a 
solution of ordinary gelatine in the usual way, and subse- 
quently dried. The amount of gelatine absorbed differs in 
a remarkable degree, as shown in table. 

Tensile Strength of the Paper. — It is interesting to note 
that the tensile strength of the waterleaf papers appears to 
remain fairly constant throughout the whole period of 
beating. But this uniformity is greatly altered by the 
operations of sizing and glazing. 



THE PEOCESS OF BEATING 



183 



Percentage of Air-dby Gelatine ^ibsorbed by the 
Waterleaf Sheets. 



Hours. 


Percentage of Size absorbed. 














1st Trial. 


2nd Trial. 


3rd Trial. 




S 


b'o 


6-0 


6-2 


5-9 


10 


5-4 


(3-8 


6-5 


6-2 


19 


3-8 


5-0 


4-5 


4-4 


21 


4-8 


3-9 


4-6 


4-4 


;^;3 


2-7 


1-7 


2-4 


2-3 


35 


2-4 


1-9 


1-7 


2-0 



These results are rather remarkable. The prolonged 
beatmg does not seem to have affected the tensile strength 
of the waterleaf, and the practical loss of strength which 
actually occurs in the more completely finished paper does 
not manifest itself until after the sizing process. The 
importance of the gelatine as a factor in the ultimate strength 
is thus clearly and strikingly demonstrated. 

Tests for Strength on Original Waterleaf Paper. 



Hours. 


Mean result of 

Readings. 

Lbs. 


Mean Strength 

of the Paper. 

Lbs. 




8 


a 
b 


14-1 
10-1 


12-1 




10 


a 
b 


15-4 
10-9 


13-2 




19 


a 
b 


16-5 
11-4 


14-0 




21 


a 
b 


15-2 

12-8 


14-0 




33 


a 
b 


•13-4 
'11-4 


12-4 




35 


a 
b 


14-5 

12-'; 


13-6 



184 



THE MANUFACTURE OF PAPER 



Tests foe, Strength on Papers, Sized oxly. 





Mean result, of 


Mean Strength 


Hourd. 


Readings. 


of the Paper. 






Lbs. 


Lbs. 


8 


a 


22-7 


20-0 




b 


17-3 




10 


a 


28-5 


23-2 




b 


18-0 




19 


a 


22-0 


21-0 




b 


19-5 




21 


a 


26-0 


21-7 




b 


17-0 




33 


a 


lo-O 


15-0 




b 


lo-O 




35 


a 


14-2 


15-3 




b 


16-0 





Tests for Strength on Paper Sized and Glazed. 





Mean result of 


Mean Strength 


Hours. 


Readings. 


of the Paper. 






Lbs. 


Lbs. 


8 


a 


25-8 


23-6 




b 


21-4 




10 


a 


28-4 


23-6 




b 


18-9 




19 


a 


27-0 


22-9 ■ 




b 


18-9 




21 


a 


24-9 


22-7 




b 


20-6 




33 


a 


16-1 


15-2 




b 


14-4 




35 


a 


17-5 


16-2 




b 


15-0 





THE PEOCESS OF BEATING 



185 



It may also be noticed that the strength of the finished 
paper after twenty hours' beating, as in class B, is equal to 
that of the paper after nine hours' beating, as in class A. 
This is curious, especially in view of the fact that the per- 
centage of gelatine in the papers of class B. is only 4*4 per 
cent, as against 6'0 per cent, in class A. 

The relation of the percentage of gelatine to the period of 
beating thus becomes a matter of interest, and well worth 





=0= 




EiG. 48. — Plan and Sectional Elevation of a " Hollander. 



investigation. The figures are suggestive of further 
experimental research along definite lines. 

Developments in Beating Engines. — Since the introduc- 
tion of the Hollander beating engine, about a.d. 1670, other 
types of beater almost too numerous to mention have been 
devised to supersede it, but the fact remains that the 
principle of the original Hollander and its general design 
are still adhered to in the engines used by paper-makers for 
high-class work. 

The alterations and improvements which have taken 



186 



THE MANUPAOTUEE OF PAPEE 



place during the last fifty years relate chiefly to the modi- 
fications naturally arising from the introduction of fibres 
not requiring such drastic treatment as rags. 

The machines now in use for reducing half-stuff to beaten 
pulp ready for the paper machine may be classified as 
follows : — 

(1) Beaters of the Hollander type, in which the circula- 
tion of the pulp in the engine and the actual beating process 

are both effected by the 
beater roll. 

(2) Beaters of the 
circulator type, in which 
the movement of the 
pulp is maintained by 
a special contrivance, 
and the beater roll used 
only for beating. 

(3) Beaters of the 
stone roll type in which 
the roll and bedplate 
are either or both com- 
posed of stone, granite, 
or similar non-metallic 
substance. 

(4) Kefiners, containing conical shaped beater rolls 
working in a conical shell fitted with stationary knives. 

The Hollander. — This beating engine in its simplest form 
consists of an oval shaped trough, divided into two channels 
by a " midfeather," which does not, however, reach com- 
pletely from one end to the other. 

In one of the channels the bed of the trough slopes up 
slightly to the place where the " bedplate " is fixed. The 
bedplate consists of a number of stout metal bars or knives 
firmly fastened into an iron frame, which lies across this 




Pig. 49. — Beating Engine with 
Pour Beater Eolls. 



THE PEOCESS OF BEATING 



187 



channel. The beater roll, a heavy cast-iron roll provided 
with projecting knives or blades arranged in clumps of 
three around the circumference, and supported on bearings 
at each side of the engine, revolves above the bedplate with 
the knives adjusted to any required distance from it, the 
raising or lowering of the beater roll for this purpose being 
effected by the use of adjustable bearings. 

The bed of the trough behind the beater roll rises sharply 
up fr«m the bedplate and then falls away suddenly, as 
shown in the diagram, forming the " backfall," 

When the engine is in operation the mixture of water 
and pulp is drawn between the knives and circulated round 
the trough. The material is disintegrated into fibres of 
the required condition, discharged over the backfall, and 
kept in a state of continual circulation, and the beating 
maintained until the stuff has been sufficiently treated. 

The dimensions of the engine vary according to the 
capacity, which is usually expressed in terms of the amount 
of dry pulp the beater will hold, and the following figures 
may be taken as giving the average sizes : — 



Lengtli . 
Widtk . 
Depth, (average) 
Diameter of roll 



2 cwt. Eiifrine. 



11 ft. Oin. 

5 ft. 6 in. 

2 ft. 3 in. 

3 ft. 6 in. 



5 cwt. Engine. 



16ft. Oin. 

8ft. Oin. 

2 ft. 9 in. 

3 ft. 6 in. 



Sundry modifications in the form and arrangement of the 
beater have been tried from time to time. In 1869 Granville 
patented the substitution of a second beater roll in place of 
the stationary bedplate for the purpose of hastening the 
operation. Kepeated attempts have been made to construct 
a beating engine with two or more rolls, but it is evident 
that such a device could hardly succeed, since it would be 



188 THE MANUFAOTUEE OP PAPEE 

impossible to ensure proj)er adjustment of the rolls, and in 
that case one roll might be doing all the work. 

The first machine o£ this type was patented in 1872 by 
Salt. Similar beaters were devised by Forbes in 1880, 
Macfarlane in 1886, Pickles in 1894, who proposed to use 
three rolls, and Partington in 1901. Hoffman describes a 
beating engine which was working in America containing 
four rolls, as shown in the diagram. 

21ie Umplierston. — A notable modification of the Hollander, 
having an arrangement by which the two channels of the 



Fm. 50. — Umplierston Beater. 

engines are placed under one another, and one which is 
largely used for fibres, is the Umpherston. Several engines 
differing in detail, but embodying the same principle, have 
been built in imitation of this one. 

Bedplates of large working surface were first tried in 
England by Cooke and Hibbert, in 1878, but in practice 
it has been found that no serious deviations from the narrow 
type of plate are of much value. As a matter of fact it is 
held by some paper-makers that one or two knives would be 
sufficient if they could be relied on to keep true and in 
proper adjustment. 



THE PEOCESS OF BEATING 



189 



The Circulating Type of Beatev. — The addition of some 
device for keeping the pulp in circulation apart from the 
action of the roll has received considerable attention. The 
early experiments in this direction with the Hollander led 
ultimately to the construction of the engine of the circulator 
type mentioned in class 2. 

Thus, in 1872, Nugent patented a special paddle to be 
used in the Hollander, by which the pulp in the trough of 
the beater was impelled towards the roll. Many other plans 




Fig. 51. — Section of Uniplierstoii Beating 
Engine. 

were tried for this purpose, and details can be seen in the 
List of Patents (see page 192). 

The introduction of the beaters with special means of 
circulating the pulp was found to be of the greatest service 
in the treatment of stuff like esparto and wood pulp, since 
these materials did not require the drastic measures neces- 
sary with rag pulp. In 1890 several engines of this class 
were being adopted, amongst which may be mentioned 
Hemmer's, Eeed's and Taylor's. The pulp discharged from 
the beater roll was drawn through an independent pipe 
or channel by means of an Archimedean screw, or a 
centrifugal pump. 

Stone Beater Rolls. — The substitution of stone for metal 
in the roll and bedplate of the engine brings about some 



190 THE MANUFACTURE OF PAPETi 

remarkable changes in the nature of the beaten stuff. The 
fibre is submitted to the action of rough surfaces rather 
than that due to the contact of sharp edges, with the result 
that the disintegration is much more rapid, and produces a 
" wet " working pulp suitable for imitation parchments and 
siniilar papers. The latest materials used for this purpose 




Fig. 52. — Nugeut's Beatiug Engitie with Paddles for Circulating 
the Palp. 

are basalt lava stone in Germany, and carborundum in 
America. 

Care is necessary in the manipulation of these beaters to 
prevent fracture of the stone parts. In the Wagg Jordan 
engine this danger is materially reduced by the construction 
of the working parts. 

Refiners. — In these engines the beater roll is a conical 
shaped drum carrying the knives, which revolve inside 
a conical shell completely lined with fixed knives. The 
fibres are thus cut up to the desired length, but before dis- 
charge from the engine they pass between two circular discs, 



THE PEOCESS OF BEATING 



191 



one stationary and the other revolving in a vertical position. 
The effect of the discs is to tear or bruise the fibres rather 
than to cut them. 

The refiner is 
best employed to 
clear or brush out 
the mass of pulp 
after a certain 
amoimt of prelimi- 
nary treatment in 
the beater, as the 
refiner cannot pro- 
duce the effects 
obtained by actual 
beating as in the 
Hollander. 

Power Consump- 
tion. — The long 
treatment required 
to thoroughly pulp 
a strong material 
demands a great 
amount of power. 
Engines differ con- 
siderably in their 
power consump- 
tion, and compari- 
sons are frequently 
made in terms of 
the power required 
to beat a given 
weight of pulp. 
But this is not always a true criterion of efficient work. 
Some types of beater are suitable for producing certain 




Fig. 53. — A "Tower" Beating Engine with 
Centrifugal Pump for Circulating Pulp. 



192 



THE MANUFACTUEE OF PAPEE 



results, and the mere substitution of a beater consuming 
less power is worse than useless unless it can be shown that 
the same effects are being obtained. The efficiency of the 
Hollander for the beating of rag pulp, in spite of the high 
power consumption, is a case in point. 

With this factor properly considered, the power required 




Fig. 54. — Working Parts of a Modern Eefining Engine. 

for beating becomes an interesting study. Many detailed 
experiments have been published from time to time, the 
most recent being those described by Beadle. 

Patents taken out in Connection with Beating 
Engines. 

1855. Paek (1170). — A smalbsteam engine was attached 
to the shaft of the beater roll, so that it could be driven direct. 



BEATING ENGINES 193 

1856. KiNGSLAND (2828). — A form of refiner in which the 
pulp was beaten by a vertical disc rotating in an enclosed 
case. 

1860. Jordan (792). — A machine devised for mixing size 
with pulp, made like a conical refining engine, the rubbing 
surface being provided with teeth or cutters. 

1860. Jordan (2019). — An engine of the refiner type, 
constructed with a conical drum rotating in a conical 
casing. The knives at the larger end of the drum are 
placed closer together than those on the smaller end. 

1863. Park (1138). — Two beaters placed side by side are 
driven by one steam engine placed between them, the 
operations being so timed that one rag engine is used for 
breaking while the other is finishing. 

1864. Ibotson (2913). — The pulp is passed continuously 
from one engine roll to another, or from one part of a 
beater roll to another part of the same roll through slotted 
plates. 

1866. Eoeckner (140). — A beating engine of the refiner 
type with conical drum and casing. 

1866. Berham (3299). — A beating engine of the conical 
type with the beater roll rotating vertically instead of 
horizontally. 

1867. Crompton (482).— Device for raising the bars in 
the beater roll as the edge of the plate wears away. 

1867. Wood (914). — Modification in the form of the beater 
bars (of little importance) . 

1867. Edge (3673).— The knives of the beater roll dis- 
tributed at equal distances apart all round the roll, alternated 
with strips of wood. 

1869. Granville (1041). — Substitution of a second beater 
roll for the stationary bed-plate, the knives being set spirally 
round the roller. 

1869. Newell (2905) .^Weight of the beater roll counter- 

p. o 



194 THE MANUFACTUEE OE PAPER 

poised to allow of the exact regulation of the pressure on the 
stuff in the beating engine. 

1870. EosE (997). — An intercepting plate fixed to the 
cover of the beating engine which causes that part of the 
stuff which was usually carried right round by the roll to fall 
back behind the backfall. 

1870. Bentlbyand Jackson (1633) — A beater roll having 
the same width as the engine, and provided with a cover 
fitted with a pipe which conducted the material back to the 
front of the roll. 

1871. Patton (1336). — Bottom of beating engine curved 
in order to prevent the stuff settling or accumulating at anj' 
portion of the machine. 

1872. Salt (1901). — A beating engine of usual type, but 
having two beater rolls and two drum washers, one pair in 
each of the two channels. 

1873. Gould (769). — A curious engine with horizontal 
shaft having a circular disc at the lower end, fitted with 
knives on the under- surface, which are in contact with fixed 
knives lying at the bottom of the vessel. The circulation 
of the pulp is effected by the centrifugal force generated. 

1873. Martin (3751). — A beating engine with two rolls 
in the same trough, the first roll working in conjunction 
with a smooth surfaced beating roll, the other being in 
contact with a bedplate of the usual type, the object of the 
first roll being to partially disintegrate the material without 
danger of choking. 

1874. Johnstone (3708). — A pulping engine in which 
the rubbing action of two grindstones one upon the other is 
utilised as a means of beating. 

1876. Gardner (307). — A beating engine in which the 
beater roll is conical in shape, working vertically in contact 
with the bottom of the beating engine, which is also conical 
in shape, the engine itself being circular. 



BEATING ENGINES 195 

1878. Cooke and Hibbert (4068). — The bedplate con- 
structed in the form of a circular segment with a much 
larger face than usual, and capable of adjustment, the 
beater roll itself being fixed in the bearings. 

1880. Forbes (692). — A long oval shaped beating engine 
divided into three channels instead ,of two. In the two 
outer channels are placed beater rolls and drum washers. 
The stuff discharged over the backfalls from the two beat- 
ing engines flows down the central channel and is circulated 
by a special paddle constructed in such a manner as to 
deliver the pulp in two equal streams into the outer channels 
to each of the beater rolls. 

1880. Umpherston (1150). — An engine constructed with 
a passage below the backfall so that the stuff circulates 
in a trough underneath the beater roll, the object being to 
ensure more effective treatment and to save floor space. 

1883. AiTCHisoN (5381). — A beating engine of usual 
form, but with the beater roll made conical in shape with 
the larger circumf srence outwards, and the bedplate placed 
on an incline parallel with the knives on the beater roll. 

1884. Mayfibld (2028).— The backfall of the beating 
engine is of entirely different construction to the ordinary 
machine, for the purpose of improving the circulation. 

1884. HoYT (11177). — An engine resembling the Um- 
pherston, but with a larger roll, the diameter of which 
is equal to the full depth of the engine, the backfall being 
in a line with the axis of the beater roll. 

1885. Jordan (7156). — Additions to the Jordan engine 
for admitting water and steam to the engine as required. 

1885. Korschilgen (9433). — The beater roll made of 
stone or of metal with a stone casing furnished with ribs 
or knives placed close together. 

1886. Hibbert (4237). — A beating engine fitted with an 
ordinary beater roll, and having in addition a heavy disc 

o2 



196 THE MANUFACTUEE OF PAPER 

rotating vertically, the disc being fitted with knives on one 
surface which rotate in contact with knives fixed on a 
stationary disc. 

1886. Kron (9885). — A device for securing better circula- 
tion of the pulp, the stuff leaving the beater roll being 
divided into two streams which are brought together again 
in front of the roll. 

1886. HoENB (10237). — A long rectangular vessel with a 
large beater roll at one end, contrived so as to force the pulp 
leaving the beater roll to pass down a partition separating 
it from the pulp going towards the beater roll. 

1886. Macfarlanb (11084). — An engine fitted with two 
beater rolls which rotate in opposite directions, the stuff 
being mixed between them. 

1887. Nacke (746). — A centrifugal circulating wheel 
rotating horizontally in the centre of the beating engine is 
used in combination with a parallel cutting disc. 

1887. Marshall (1808). — A conical refiner having in 
addition at its large end a pair of grinding discs fitted with 
knives and rotating vertically. 

1887. VoiTH (6174). — An alteration to the covers of the 
beater rolls which prevent stuff from being carried round 
the cylinder, and cause it to pass over the backfall freely. 

1890. Hemmer (17483). — A beating engine provided with 
a separate return channel for the pulp, the circulation 
through the channel being effected by a small centrifugal 
pump. 

1890. A. E. EiiED (19107). — A beating engine in which 
the pulp discharged over the backfall is delivered to the 
front of the beater roll by a screw propeller. 

1891. Karger (11564). — A beater similar to the Umpher- 
ston, but provided with a circulating roll fitted with radial 
projections which delivers the stuff to the front of the beater 
roll. 



BEATING ENGINES 197 

1892. Taylor (7397). — A beating engine in which the 
beater roll operates in a closed chamber above the vat full 
of pulp, the stuff being continually circulated by a centri- 
fugal pump which draws the stock from the bottom of the 
vat and delivers it to the beater roll. 

1892. Annandale (9173). — A conical- shaped beating 
engine with the beater roll rotating in a vertical position; 
the larger end of the cone being downwards. 

1S92. Umphbrston (15766). — An addition to the beating- 
engine arranged so that two fixed bedplates are used 
instead of one. 

1892. Miller (15947). — A machine in which two fixed 
bedplates are used, one below the beater roll and one above, 
the engine being fitted with suitable baffle plates to ensure 
proper circulation. 

1893. Pearson and Bertram (11956). — A special form of 
refining engine in which the pulp is subjected to the action 
of discs rotating vertically, the knives being arranged 
radially on the disc. 

1893. Caldwell (15332). — A rotary beating engine in 
which the beating surfaces admit of accurate adjustment. 

1894. CoRNETT (945). — An outlet is fixed to the beater 
roll casing close to the discharge from the bedplate, so that the 
roll is not impeded by the weight of the pulp, which is 
subsequently pumped to the front of the beater roll. 

1894. Shand and Bertram (4136). — A beating engine 
similiar to the Umpherston beater in which the beater roll 
is raised up out of the pulp and the circulation effected by 
means of a worm which delivers the pulp to the front of the 
beater roll. 

1894. Pickles (20255). — A beating engine somewhat 
similar to an Umpherston, but fitted with three beater rolls 
and bedplates. 

1894. HiBiiERT (25040), — A beating engine in which the 



198 THE MANUFACTUEE OF PAPER 

pulp is beaten between two discs rotating vertically, the 
pulp being brought between the discs through the hollow 
shaft of one of the discs. 

1895. Brown (1615). — An engine in which the beater roll 
and bedplate both revolve, but in opposite directions, and at 
different speeds in order to draw out the fibres. 

1895. Schmidt (24730). — A device by means of which the 
pulp discharged from the beater roll is diverted into supple- 
mentary channels on either side which come together again 
in front of the beater roll, 

1900. Hadfield (2468). — An adjustable bafQe board 
passing through the cover of the beater roll which 
prevents the pulp being carried round by the roll, more 
or less. 

1900. Masson and Scott (5367). — An improved form of 
Taylor beating engine in which the chest of the engine is 
vertical instead of horizontal. 

1901. Partington (24654). — A continuous elliptical 
trough provided with two beater rolls. 

1902. PiCARD (19635). — Improvements in the form of the 
propellers used for circulating the material, 

1902. Pope and Mullen (22089).^ — Improvements in 
propellers for circulating the pulp. 

1903. Annandalb (26012). — A new form of beating 
engine somewhat on the principle of a steam turbine. 

1905. Bertram (1727). — A beater similar to Masson's 
tower beater, but in which a pair of reciprocating wheels 
fitted with projecting knives are used instead of a centrifugal 
pump. 

1907, Wagg's Jordan Engine (6788), — A conical refiner 
fitted with specially arranged metal or stone knives. 



CHAPTER X 

THE DYEING AND COLOURING OF PAPER PULP 

Nearly all papers, even those commonly regarded as 
white, are dyed with some proportion of colouring matter. 
With the ordinary writing and jDrinting papers the process 
is usually confined to the addition of small quantities of 
pigments or soluble colours sufficient to tone the pulp and 
correct the yellow tint which the raw material possesses 
even after bleaching. In the case of cover papers, tissues, 
and similar coloured papers, the process is one of dyeing as 
it is generally understood. 

The colouring matters which have been employed by the 
paper-maker are — 

Pigments. 

(A) Added to the pulp in the form of mineral in a finely 
divided state. 

Yellow. — This colour is obtained by the use of ochres, 
which are natural earth colours of varying shades, 
from bright yellow to brown. 
Red. — Ordinary red lead. 

Various oxides of iron, such as Indian red, Venetian 
red, red ochre, rouge. 
Blue. — Smalts — An expensive pigment prepared by grind- 
ing cobalt glass. 

Ultramarine — A substance of complex composition 
prepared by heating a mixture of china clay, 
carbonate of soda, sulphate of soda, sulphur, 



2C0 THE MANUFACTUEE OF PAPER 

charcoal, and sometimes quartz, rosin and in- 
fusorial earth. 
Prussian Blue — A compound prepared by adding 
potassium ferrocyanide to a solution of ferrous 
sulphate. 
Brown.— Natural earth colours, such as sienna, umber, 

Vandyke brown. 
Black. — Lamp-black, bone-black, Frankfort black. 
(B) Produced by the reaction of soluble salts upon one 
another when added to the pulp in the beating engine. 
Yellow. — Chrome Yellow — The paper pulp is first im- 
pregnated with acetate of lead, and potassium or 
sodium bichromate added. This precipitates the 
chromate of lead as a yellow pigment. 
Chrome Orange — The addition of caustic alkali to the 
bichromate solution converts the chrome yellow into 
an orange. 
Blue. — Prussia7i Blue — The paper pulp impregnated with 
iron salts is treated with potassium ferrocyanide. 
The blue colour is at once obtained. 
Brown. — Iron Buf — A light yellow-brown colour due to 
the precipitation of ferrous sulphate by means of an 
alkali. 
Bronze. — Manganese chloride followed by caustic soda. 

Soluble Colouks. 

(A) Natural Dyes. These colouring matters are now 
seldom used. 

Yellow and Brown. — The vegetable extracts, such as 

fustic, quercitron, cutch, turmeric, have practicall}^ all 

been replaced by aniline colours. 
Red. — Madder (Turkey red). Brazilwood, cochineal (a dye 

obtained from dried cochineal insects). Safflower. 



TBE DYEING AND COI-OUEING OF PAPEE PULP 201 

Black. — Logwood, used in conjunction with an iron salt. 
Cutch, used with an iron salt. 

(B) Coal Tar Dyes. The dyeing and colouring of paper 
pulp by means of the artificial organic substances has 
become a matter of daily routine, the expensive natural 
dyes and the ordinary pigments having been almost 
completely superseded. The numerous colouring matters 
available may be classified either by reference to their 
chemical constitution or simply on general lines, having 
regard to certain broad distinctions. 

If the latter classification is taken, then the dyes familiar 
to the paper-maker may be divided into— 

(a) Acid dyes, so called because the full effect of the 
colouring matter is best obtained in a bath showing an 
acid reaction. 

(b) Basic dyes, so called because the colour is best 
developed in an alkaline solution, without any excess 
of mordant. 

(c) Substantive dyes, which do not require the use of a 
mordant, as the colour is fixed by the fibre without 
such reagents. 

Some of the most frequently used colouring matters are 
shown in the accompanying table on page 202. 

The distinction between acid and basic dye-stuffs is largely 
due to certain characteristics possessed by many of them. 
Thus magenta, which is the salt of the base known as 
Eosaniline, belonging to the basic colouring matters, a group 
of dyes which do not possess the fastness of colour peculiar 
to acid dyes, has a limited application. But by treatment 
with sulphuric acid magenta is converted into an acid 
magenta, and this dye has wider application than the basic 
salt. Similarly the basic dye called aniline blue is insoluble 
in water, and therefore has only a limited use, but by treat- 
ment with sulphuric acid it is converted into alkali blue. 



202 



THE MANUFACTUEE OP PAPER 



soluble blue and so on, which dissolve readily in water and 
are good fast colours. The acid dyes generally have a 
weaker colouring power than the basic dyes, but they 
produce very even shades. 

The difference in the composition of the basic and acid 
dyes is taken advantage of in the dyeing of paper pulp to 
secure a complete distribution of the colouring matter upon 



Colour. 


Acid. 


Basic. 


Substantive. 


Yellow 


Metanil yellow. 


Auramine. 


Cotton yellow. 


and 


Paper yellow. 


Cbrysoidine. 


Chrysophenine. 


Orange. 


Orange II. 
Napbtbol yellow S. 
Quinoline yellow. 






Red. 


Fast red A. 


Ebodamine. 


Congo red. 




Cotton scarlet. 


Paper scarlet. 


Benzopurpurin. 




Erythrine. 


Sat'ranine. 


Oxamine red. 




Ponceau. 


Magenta. 




Blue 


Water blue 1 N. 


Metbylene blue. 


Azo blue. 


and 


Fast blue. 


Victoria blue. 




Violet. 


Acid violet. 


New blue. 
Indoine blue. 
Methyl violet. 
Crystal violet. 




Brown 


Napbthylaniine brown. 


Bismarck brown. 

Vesuvine. 




Black 


Nigrosine. 
Brilliant black B. 


Coal Black B. 




Green 




Diamond green. 
Malachite green. 





the puljp, with the result that the intensity of colour is 
increased, its fastness strengthened, and the process of 
dyeing generally rendered more economical. This is 
effected by the judicious addition of a suitable acid dye to 
the pulp already coloured with the basic dye. 

The direct colouring matters have but a very limited 
application for paper dyeing owing to their sensitiveness to 
acids and alkalies. 



THE DYEING AND COLOURING OF PAPER PULP 203 

In the colouring of paper pulp, attention is given to many 
important details, such as : — 

Fading of Colour. — Some loss of colour almost invariably 
occurs even with dyes generally looked upon as fast to light. 
The shade or tint of the paper is affected not only by exposure 
to light, but by contact of the coloured paper with common 
boards on which it is often pasted. The alkalinity of straw 
boards, for example, is frequently one source of serious 
alteration of colour, and the acidity of badly made pastes 
and adhesives another. 

In all such cases, the dyes must be carefully selected in 
order to obtain a coloured paper which will show a minimum 
alteration in tint by exposure to light or by contact with 
chemical substances. This is particularly necessary in 
coloured wrapping paper used for soap, tea, cotton yarn, 
and similar goods. 

Unevenness of Colour. — The different affinity of the 
various paper-making fibres for dyes is apt to produce an 
uneven colour in the finished paper. This is very notice- 
able in mixtures of chemical wood pulp or cellulose and 
mechanical wood pulp. The lignocellulose of the latter has 
a great affinity for basic dyes, and if the required amount 
of dye is added to a beater containing the mixed pulps in 
an insufficiently diluted form, the mechanical wood pulp 
becomes more deeply coloured than the cellulose. If the 
former is a finely ground pulp, the effect is not very notice- 
able, but if it is coarse, containing a large number of coarse 
fibres, then the paper appears mottled. The defect is still 
further aggravated when the paper is calendered, esj)ecially 
if calendered in a damp condition. In that case the 
strongly coloured fibres of mechanical wood are very 
prominent. 

When dyes have been carelessly dissolved and added 
to the beating engine without being properly strained, 



204 THE MANUFACTURE OF PAPER 

unevenness of colour may often be traced to the presence of 
undissolved particles of dye. 

Irregular Colour of the two Sides. — Many papers exhibit 
a marked difference in the colour of the two sides. When 
heavy pigments are employed as the colouring medium, the 
under side of the sheet, that is, the side of the paper in 
contact with the machine wire, is often darker than the 
top side. The suction of the vacuum boxes is the main 
cause of this defect, though the amount of water flowing on 
to the wire, the " shake " of the wire, and the extent to 
which the j)aj)er is sized are all contributory causes. By 
careful regulation of these varying conditions the trouble is 
considerably minimised. 

The under surface of the paper is not invariably darker 
than the top surface. With pigments of less specific gravity 
the reverse is found to be the case. This is probably to be 
explained by the fact that some of the colouring matter 
from the under side is drawn away from the paper by the 
suction boxes, and the pigment on the top side is not drawn 
away to any serious extent, because the layer of pulp below 
it acts as a filter and promotes a retention of colour on the 
top side. 

It is interesting to notice that this irregularity sometimes 
occurs with soluble dyes, as for example in the case of 
auramine. The decomposition of this dye when heated to 
the temperature of boiling water is well known, and the 
contact of a damp sheet of paper coloured by auramine 
with the surfaces of steam-heated cylinders at a high 
temperature brings about a partial decomposition of the 
dye on one side of the j)aper. Generally speaking, acid 
dyes are more sensitive to heat than basic dyes. 

The presence of china clay in a coloured paper is also an 
explanation of this irregular appearance of the two sides. 
China clay readily forms an insoluble lake with basic 



THE DYEING AND COLOUEING OF PAPER PULP 205 

dyes, and when the suction boxes on the machine are worked 
with a high vacuum the paper is apt to be more deeply 
coloured one side than another. 

Tlie Machine Backwater. — Economy in the use of dyes to 
avoid a loss of the colouring matter in the " backwater," or 
waste water from the paper machine, is only obtained by 
careful attention to details of manufacture on the one hand 
and by a knowledge of the chemistry of dyeing on the 
other The loss is partly avoided by regulating the amount 
of water used on the machine, so that very little actually 
goes to waste, and further reduced by ensuring as complete 
a precipitation of the soluble dye as possible. 

The acid dyes generally do not give a colourless back- 
water, and all pulps require to be heavily sized when acid 
dyes are used. 

The basic dyes are more readily precipitated than the 
acid dyes, particularly if a suitable mordant is used, even 
with heavily coloured papers. The addition of an acid dye 
to pulp first coloured with a basic dye is frequently resorted 
to as a means of more complete precipitation. 

Dyeing to Sample. — The matching of colours has been 
greatly simplified through the publication of pattern books 
by the firms who manufacture dyes, in which books full 
details as to the composition of the paper, the proportion of 
colour and the conditions for maximum effects are fully 
set out. The precise results obtained by treating paper 
pulp with definite proportions of a certain dye, or a mixture 
of several dyes, is determined by experimental trials. A 
definite quantity of moist partially beaten and sized pulp, 
containing a known weight of air-dry fibre, is mixed with a 
suitable volume of water at a temperature of 80° to 90° F. 
and the dye-stuff added from a burette in the form of a 
1 per cent, solution. If preferred a measured volume of 
a 1 per cent, solution of the dye can be placed in a mortar. 



206 THE MA.NUFACTUEE OF PAPER 

and the moist pulp, previously squeezed out by hand, added 
gradually and well triturated with the pestle. 

The dyed mixture is then suitably diluted with water, 
made up into small sheets of paper on a hand mould or a 
siphon mould, and dried. 

The effect of small additions of colour to the contents of 
a beating engine is frequently examined in a rough and 
ready way by the beaterman, who pours a small quantity of 
the diluted pulp on the edge of the machine wire while the 
machine is running. This gives a little rough sheet of 
paper very quickly. 

The comparison of the colour of a beaterfull of pulp with 
the sample paper which it is desired to match is also 
effected by reducing a portion of the paper to the condition 
of pulp, so that a handful of the latter can be compared 
with a quantity of pulp from the engine. This is not 
always a reliable process, especially with papers coloured 
by dyes which are sensitive to the heat of the paper machine 
drying cylinders. 

Detection of Colours in Papers. — The examination of 
coloured papers for the purpose of determining what dyes 
have been employed is a difficult task. With white papers 
which have been merely toned the proportion of dye is 
exceedingly small, and a large bulk of paper has to be 
treated with suitable solvents in order to obtain an extract 
containing sufficient dye for investigation. 

With coloured papers dyed by means of pigments, the 
colour of the ash left on ignition is some guide to the 
substance used, a red ash indicating iron oxide, a yellow 
ash chromate of lead, and so on. 

With papers dyed by means of coal tar colours the 
nature of the colouring matter may be determined by the 
methods of analysis employed for the examination of 
textile fibres. 



THE DYEING AND COLOUEINa OF PAPER PULP 207 

The following hints given hy Kollmann will be found 
useful : — 

Tear up small about 100 grammes of paper, and boil it 
in alcohol, in a flask or a reflux condenser. This must be 
done before the stripping with water, so as to extract the 
size which would otherwise protect the dye from the water. 
Of course the alcohol treatment is omitted with unsized 
paper. The paper is now boiled with from three to five 
lots »t water, taking each time only just enough to cover 
the paper. This is done in the same flask after pouring o& 
any alcohol that may have been used, and also with the 
reflux condenser. The watery extract is mixed with the 
alcohol extract (if any). Three cases may occur: — (1) The 
dye is entirely stripped, or very nearly so. (2) The dye is 
partly stripped, what remains on the fibres showing the 
same colour as at first or not. (3) The dye is not stripped. 
To make sure of this the solution is filtered, as the presence 
in it of minute fragments of fibre deceive the eye as to the 
stripping action. In the first two cases the mixed solutions 
are evaporated down to one half on the water bath, filtered, 
evaporated further, and then precipitated by saturating it 
with common salt. The dye is thrown out at once, or after 
a time. It may precipitate slowly without any salt. The 
precipitated dye is filtered off and dried. To see whether 
it is a single dye or a mixture, make a not too dark solution 
of a little of it in water, and hang up a strip of filter paper 
so that it is partly immersed in the solution. If the latter 
contains more than one dye they will usually be absorbed 
to different heights, so that the strip will show bands of 
different colours crossing it. If it is found that there is 
only one dye, dissolve some of it in as little water as 
possible, and mix it with " tannin-reagent," which is made 
by dissolving equal weights of tannin and sodium acetate 
in ten times the weight of either of water. If there is a 



208 THE MANUFACTUEE OF PAPER 

precipitate there is a basic dye, if not, an acid dye. In the 
former case mix the strong sokition of the dye with con- 
centrated hydrochloric acid and zinc dust, and boil tiJl the 
colour is destroyed. Then neutralise exactly with caustic 
soda, filter, and put a drop of the filtrate on to wliite filter 
paper. If the original colour soon reappears on drying, 
we draw the following conclusions : — 

(a) The colour is red ; the dye is an oxazine, thiazine, 
azine, or acridine dye, e.g., safranine. (b) It is orange or 
yellow ; the dye is as in (a), e.g., phosphine. (c) It is 
green; the dye is as in (a), e.g., azine green, {d) It is 
blue ; the dye is as in (a), e.g., Nile blue, new blue, fast 
blue, or methylene blue, (e) It is violet ; the dye is as in 
(a), e.g., mauveine. If the original colour does not reappear 
on drying, but does so if padded with a 1 per cent, solution 
of chromic acid, we draw the following conclusions : — 

(a) The colour is red ; the dye is rhodamine or f uchsine, 
or one of their allies, (b) It is green ; the dye is malachite 
green, brilliant green, or one of their allies, (c) It is blue ; 
the dye is night blue, Victoria blue, or one of their allies. 
(d) It is violet ; the dye is methyl violet, crystal violet, or 
one of their allies. 

If the original colour does not reappear even with 
chromic acid, it was in most cases a yellow or a brown, 
referable to auramine, chrysoidine, Bismarck brown, 
thioflavine, or one of their allies. 

If the tannin reagent produces no precipitate, reduce 
with hydrochloric acid and zinc, or ammonia and zinc, and 
neutralise and filter as in the case of a basic dye. The 
solution when dropped on to white filter paper may be 
bleached (a), may have become a brownish reel (b), may 
have been imperfectly and slowly bleached (c), or may 
have undergone no change (d). 

(a) If the colour quickly returns the dye is azurine. 



THE DYEING AND COLOUEING OF PAPER PULP 209 

indigo-carmine, nigrosine, or one of their allies. If it 
returns only on padding with a 1 per cent, solution of 
chromic acid, warming, and holding over ammonia, some 
of the dye is dissolved in water mixed with concentrated 
hydrochloric acid, and shaken up with ether. If the ether 
takes up the dye, we have aurine, eosine, erythrine, 
phloxine, erythrosine, or one of their allies. If it does 
not, we have acid fachsine, acid green, fast green, water 
blue, 'patent blue, or one of their allies. If the colour 
never returns, heat some of the dye on platinum foil. If it 
deflagrates with coloured fumes, the dye is aurantia, 
naphthol yellow S., brilliant yellow, or one of their allies. 
If it does not deflagrate, or very slightly, dissolve a little of 
the dye in one hundred times its weight of water, and dye a 
cotton skein in it at the boil for about fifteen minutes. 
Then rinse and soap the skein vigorously. If the dyeing 
is fast with this treatment we have a substantive cotton 
yellow or thiazine red ; if it is not, we have an ordinary azo 
dye. {b) The dye is an oxyketone, such as alizarine. 
(c) The dye is thiazol yellow, or one of its allies, (d) The 
dye is thioflavine S., quinoline yellow, or one of their 
allies. 

If the dye is not stripped by alcohol and water, it is 
either inorganic or an adjective dye, such as logwood black, 
cutch, fustic, etc. ; and we proceed according to the colour 
as follows : — 

If it is red or brown, the dyed fibre is dried and divided 
into two parts. One is boiled with bleaching powder. If 
it is bleached entirely or to a large extent, the dye is cutch. 
If the bleach has no action, incinerate some of the dyed 
fibre in an iron crucible and heat the ash on charcoal before 
the blowpipe. If a globule of lead is formed, we have 
Saturn red. The second portion is boiled with concentrated 
hydrochloric acid. If there is no action, we have Cologne 

p. p 



210 THE MANUFACTUEE OF PAPER 

umber ; if there is partial action, we have real umber ; if 
the dye dissolves completely to a yellow solution, we have 
an ochre ; if the solution is colourless instead of yellow, 
and chlorine is evolved during solution, we have manganese 
brown. 

If the colour is yellow or orange, boil with concentrated 
hydrochloric acid. If we get a green solution and a white 
residue, we infer chrome j^ellow or orange. If we get a 
yellow solution, we boil it with a drop or two of nitric acid 
and then add some ammonium sulpbocyanide. A red 
colour shows an ochre or Sienna earth. 

If the colour is green, boil with caustic soda lye. If the 
fibre turns brown, we have chrome green. If no change 
takes place, boil with concentrated hydrochloric acid. A 
yellow solution shows green earth ; a red colour logwood 
plus fastic. 

If the colour is blue or violet, boil with caustic soda lye. 
If the fibre turns brown, we have Prussian blue. If no 
change takes place, boil with concentrated hydrochloric 
acid. A yellow solution shows smalts. If the colour is 
destroyed, and the smell of rotten eggs is developed, we 
have ultramarine. 

If the colour is black, warm with concentrated hydro- 
chl'oric acid containing a little tin salt. If the black is 
unchanged, we have a black pigment. If we get a pink to 
deep red solution we have logwood black. 

By means of the tests above detailed at length the group 
to which the dye belongs is discovered, and often the actual 
dye itself. Once the group is known it is generally easy, 
by means of the special reactions given in many books, 
e.g., in Schultz and Julius's " Tabellarische Ubersicht," 
to identify the particular dye. 

When one has to deal with a single dye and simply 
desires to determine its group, the following table, due to 



THE DYEING AND COLOURING OF PAPER PULP 211 

J. Herzfeld, will suffice. Originally intended for textiles, it 
will serve, with some modifications here made in it, for the 
rapid testing of paper. 

1. — Eed and Keddish Bkown Dyes. 

Boil the paper with a mixture of alcohol and sulphate of 
alumina. If no dye is extracted or a fluorescent solution is 
formed, we have an inorganic pigment, or eosine, phloxine, 
rhodaraine, safranine, or one of their allies. Add bleaching 
powder solution, and heat. If the paper is bleached, add 
concentrated hydrochloric acid. A violet colour shows 
safranine or an analogue. If there is no colour, but the 
fluorescence disappears, we have eosine, phloxine, rhoda- 
mine, or one of their allies. If the paper is not bleached 
test for inorganic colouring matters. Cutch brown is partly 
but not entirely bleached. 

If the alumina solution gives a red or yellow solution 
without fluorescence, add to it concentrated sodium bisul- 
phite. If bleaching takes jplace, heat a piece of the paper 
with dilute spirit. A red extract shows sandal wood, fuch- 
sine, etc. If there is little or no extract, we have acid 
fuchsine or one of its allies. If the bisulphite causes no 
bleaching, boil a piece of the paper with very dilute hydro- 
chloric acid. If the colour is unchanged, heat another 
piece of the paper with dilute acetate of lead. If no change 
takes place, we have an azo dye. If the colour turns to a 
dark brownish red, we have cochineal or the like. If the 
boiling with very dilute hydrochloric acid darkens the colour 
we have a substantive cotton dye. 

2. — Yellow and Orange Dyes. 

Heat some of the paper with a not too dilute solution of 
tin salt in hydrochloric acid. If the colour is unchanged, 

p 2 



212 THE MANUFACTUEE OP PAPER 

with a colourless or yellow solution, boil some more paper 
with milk of lime. A change to reddish or brown shows 
turmeric or a congener. Absence of change shows phosphine, 
quinoline yellow, or a natural dye-stuff. If the acid tin 
solution turns the paper red, and then quickly bleaches it 
to a pale yellow, we have fast yellow, orange IV., metanil 
yellow, brilliant yellow, or the like. If the tin turns the 
paper greyish, heat another portion with ammonium 
sulphide. A blackening shows a lead or iron yellow. 
If there is no change, we have naphthol yellow, auramine, 
azofiavine, orange II. , chrysoidine, or one of their allies. 

3. — Gkeen Dyes. 

Heat a sample of the paper in dilute spirit. If the spirit 
acquires no colour, warm for a short time with dilute sul- 
phuric acid. If both paper and solution become brownish 
red, we have logwood plus fustic. If this fails, boil with 
concentrated hydrochloric acid. A yellow solution shows 
green earth. If this fails, boil with concentrated caustic 
soda. Browning shows chrome green. If the spirit 
becomes blue, it is a case of paper which has been topped 
with blue on a yellow, brown, or green ground. The solu- 
tion and the insoluble part are separately tested. The case 
is probably one of an aniline blue dyed over a mineral 
pigment. If the spirit becomes green, heat with dilute 
hydrochloric acid. If the fibre is completely or nearly 
bleached, and the acid turns yellow, the dye is brilliant 
green, malachite green, or one of their allies. 

4. — Blue and Violet Dyes. 

Heat some of the paper with dilute spirit. If the alcohol 
remains colourless, we have Prussian blue or ultramarine. 
If it becomes blue or violet, shake some of the paj^er with 



THE DYEING AND COLOUEING OF PAPEE PULP 218 

concentrated sulphuric acid. A dirty olive green shows 
methylene blue, and a brownish colour shows spirit blue, 
water blue, Victoria blue, methyl violet, etc. If the spirit 
turns yellow, and the colour of the paper changes, we have 
wood blue or wood violet. 



CHAPTEE XI 



PAPER MILL MACHINERY 



In the case of common printings and writings, which 
form the great bulk of the paper made, the possibihty of 
one mill competing against another, apart from the im- 
portant factor of the cost of freight, coal, and labour, is 
almost entirely determined by the economy resulting from 
the introduction of modern machinery. 

The equipment of an up-to-date paper mill, therefore, 
comprises all the latest devices for the efficient handling of 
large quantities of raw material, the economical production 
of steam, and the minimum consumption of coal, matters 
which are of course common to most industrial operations, 
together with the special machinery peculiar to the manu- 
facture of paper. 

The amount of material to be handled may be seen from 
the table on page 215, which gives the approximate quantities 
for the weekly output of a common news and a good print- 
ing paper. 

Economy in Coal Consumption. — The reduction to a 
minimum of the amount of coal required for a ton of paper 
has been brought about by the use of appliances for the 
better and more regular combustion of the coal, such as 
mechanical stokers, forced and induced draught, the intro- 
duction of methods for utilising waste heat in flue gases 
by economisers, and the waste heat in exhaust steam and 
condensed water by feed-water heaters, the adoption of 
machines for securing the whole energy of tbe live steam 



PAPER MILL MACHINEEY 



215 



by means of superheaters, adequate insulation of steam 
mains and pipes, high pressure boilers, and engines of most 
recent design. 

The firing of steam boilers is now conducted on scientific 
principles, the coal being submitted regularly to proper 
analysis for calorific value, the evaporative power of the 
boilers being determined at intervals by adequate trials, 
the condition of the waste flue gases being automatically 

Table showing the Materials required for News 
AND Printings. 



- 


Common News. 


Good Printings. 


Weekly output of paper, say . 


600 tons 


250 tons 


Mechanical wood pulp, moist, 






50 per cent, dry . 


800 „ 


Nil. 


Chemical wood pulp, dry . 


200 „ 


150 tons 


Esparto 


Nil. 


200 „ 


Soda ash ..... 


Nil. 


16 „ 


Coal 


600 tons 


800 ,, 


Lime ..... 


Nil. 


45 ,, 


China clay . . . . 


60 tons 


25 ,, 


Bleach ..... 


Nil. 


30 ,, 


Alum, rosin, and chemicals 


20 tons 


20 ,, 


Water, per ton paper 


8,000 gallons 


40,000 gallons 



recorded in order to obtain regular and maximum com- 
bustion. 

The Sarco Combustion Recorder. — This instrument is a 
device which automatically records the percentage of car- 
bonic acid gas in the waste gases from boiler furnaces. The 
flue gases are analysed at frequent and regular intervals, 
and the results of the analysis can be seen on a chart 
immediately, so that it is possible to determine the effect of 
an alteration in the firing of the boilers within two minutes 
of its taking place. The apparatus is rather complicated, 
but the principle upon which it is based is simple. 



216 



THE MANUFACTURE OP PAPEE 



Measured quantities of the flue gases are drawn into 
graduated glass tubes and brought into contact with strong 
caustic soda solution, which absorbs all the carbonic acid 
gas. The remaining gases not absorbed by the caustic soda 

are automatically mea- 
sured and the percentage 
of carbonic acid gas re- 
gistered on the chart. 

The use of suitable 
boiler feed-water is also 
an important factor in 
modern steam - raising 
plant. The hot condensed 
water from the paper 
machine drying cylinders, 
and exhaust steam from 
the engines and steam- 
pipes, is returned to the 
stoke-hole to be utilised 
in heating up the cold 
water which has been 
previously softened by 
chemical treatment. 

Water Softening. — The 
water softeners available 
on the market are numer- 
ous, and as each possesses 
special advantages of its 
would be almost invidious to select any one for 




Fig. 55. — Conventional Diagram of a 
Water Softening Plant. 

A. Water supply. 

B. Kegulatiiig tank. 

C. Lime mixer. 

D. Soda tank. 

E. Settling tank and lilter. 

F. Outlet for softened water. 



own, it 
particular notice. 

They are based upon the principle of mixing chemicals 
with the water to be treated, so as to precipitate the matters 
in solution and give a boiler feed-water free from carbonates 
and sulphates of lime and magnesia. The chemicals are 



PAPEE MILL MACHINEEY 



217 



added in the form of solutions of carefully regulated 
strength to the water, which flow in a continuous stream 
into a tank. The flow of the water and chemical reagent is 
adjusted by previous analysis. 

The various machines differ in details of construction, and 
in the methods by which the mixing of the water and re- 
agents is effected. The object to be achieved is the complete 
precipitation of the dissolved salts and the production of a 
cleap" water, free from sediment, in an apparatus that will 
treat a maximum quantity of water at a cheap rate per 
1,000 gallons. 

The process needs proper attention. The addition of 
reagents in wrong proportions will do more harm than 
good, and possibly result in hardening the water instead of 
softening it. The following may be quoted as an example : — 



Composition of Water. 


Before 

Treatment. 


After 
Treatment. 


Change. 


Calcium carbonate . 
Calcium oxide (lime) 
Calcium silicate 
Calcium sulphate 
Magnesia .... 
Ferric oxide, etc. 


13-863 
00 
2-062 
1-625 
0-0 
0-447 


38-920 
14-300 
3-591 
2-121 
0-266 
0-987 


25-057 gain 
14-300 ,, 
1-529 „ 
0-496 ,, 
0-J66 ,, 
0-540 ,, 


Scale forming minerals . 


17-997 


60-185 


42-188 gain 


Calcium chloride 
Magnesium chloride 
Sodium chloride 


1-331 

0-672 
0-478 


2-114 

0-0 

0-476 


0-783 gain 
0-672 loss 
0-003 ,, 


Soluble salts . 


2-482 


2-590 


0-108 gain 


Total mineral matter 


20-479 


62-776 


42-297 gain 


Carbonic acid gas 
Oxygen gas 


9-71 
0-66 


0-0 
0-66 


9-71 loss 
0-0 



Treatment required: 1-8 lbs. of lime, 0-2 lbs. soda ash per 1,000 
gallons. Apparently 5-5 lbs. of lime were being used and no 
soda (Stromeyer). 



218 



THE MANUFACTUEE OF PAPER 



Superheated Steam. — The effective application of the 
energy of the high pressure steam is probably one of the 
most important problems in paper mill economy. The use 
of superheated steam is being extended in every direction, 
and, in addition to the advantages obtained in the steam 
engine itself, its wider possibilities for the boiling of esparto, 
wood, and fibres generally have been noted. The following 
case may be quoted as the result of a trial at a paper mill, 
showing for stated conditions the advantages of superheated 
steam : — 





Superheated 


Ordinary 




Steam. 


Steam. 


Duration of test hours . 


26 


34 


Coal consumed (lbs.) — 






Per hour .... 


610-5 


661-5 


Per 1 h.-p. hour . 


1-83 


2-08 


Water evaporated (lbs.) — 






Per hour .... 


4,832 


5,679 


Per 1 h.-p. hour. 


14-55 


17-8 


From and at 212^ F. . 


8-7 


8-94 


Steam, temperature F. . 


464 


334 


Pressure .... 


90-3 


90-8 


Steam engine — 






1 h.-p. total 


331-5 


323-2 


Temperature F. . 


381-8 


333-8 


Coal used per 1 h.-p. — 






Per hoiu- at boiler 


1-83 


2-08 



This appears to show a saving of 12 per cent. 

Gas Producers. — The substitution of gas for steam in the 
paper mill has not yet proved a success. The fact that heat 
is required for the drying cylinders of a paper machine, and 
that the heat is most cheaply and readily obtained in the 
form of exhaust steam from the engines driving the paper 
machine, militates considerably against economies which 
might otherwise be possible. The difficulties of heating 



PAPER MILL MACHINERY 219 

such cylinders, or rather of properly controlling and regu- 
lating the temperature by any other means than steam, may 
easily be surmised. 

Gas engines of over 200 h.-p. seem to give considerable 
trouble at present, but no doubt in course of time the 
required improvements will be effected. 

It is generally supposed that gas producers can only be 
economical when utilised for the production of gas on a large 
scaFe, and for distribution to engines of smaller capacity 
than the main steam engine required in a paper mill. The 
peculiar conditions of the manufacture of paper do not 
appear to be favourable to the adoption of the gas producer 
system in its present form. 

Motive Power. — The paper-maker has taken advantage of 
every modern improvement in steam engines for the purpose 
of reducing the cost of motive power. Amongst other 
alterations in this direction the use of a high speed enclosed 
engine and the employment of the modern steam turbine 
may be noted. 

In the enclosed engine the working parts are boxed in by 
a casing fitted with oil-tight doors. The cranks and con- 
necting rods splash into the oil, which is thus thrown about 
in all directions, so as to ensure sufficient lubrication. 
Another feature of this engine is the variable speed, and it 
is possible to run the paper machine at speeds varying from 
100 to 500 ft. per minute without the use of change 
wheels. 

Electrical Driving.— The application of electricity for 
motive power has made steady advances in the paper mill. 
At first it was limited to the driving of machinery in 
which variations of speed or load were not required to any 
large extent, but of recent years beating engines, calenders, 
and paper machines have all been fitted with electrical 
drives. 




Fig. 56. — An "enclosed" Steam Engine. 



PAPER MILL MAOHINEEY 221 

The following details relate to the installation at the 
Linwood Paper Mills : — 

The installation consists of 250-K.W. steam dynamos. 
The engines are Willan's high speed triple expansion, 
working with a boiler pressure of 250 lbs. per square inch 
at the stop valve, the steam being superheated to give a 
temperature of 500° Fahr. at the engine. By means of jet 
condensers a vacuum of 25 to 25^ inches is obtained on the 
engiiftes. The two boilers are of the Babcock type, and 
have 3,580 square feet of heating surface each. The furnaces 
have chain grate stokers, and the boilers are arranged with 
their own superheaters. The motor equipment consists of 
eight 80, two 50, and ten 25 B.H.P. motors. 

Six of the 80 B.H.P. drive the beating engines, and it has 
been found that the motors readily respond to an overload 
of 50 per cent, without beating or other trouble. To remedy 
the excessive and sudden variation a belt drive was adopted. 
An 80 motor drives the pulp refining engine. The two 
paper-making machines have each two motors, one a 25 and 
a 50 and the other two 25 B.H.P. motors. The speed can 
be regulated with exactitude. The auxiliary plant of the 
paper-making machine, pumps, agitators, etc., is worked 
from lines of shafting driven by motors. 

Calender motors are of the variable speed type, being 
designed to run from 100 revolutions per minute to 600 
revolutions per minute. Variations from 300 to 600 
revolutions per minute can be regulated by the shunts, the 
loss being negligible. Several of the motors are geared up 
to the various machines, as is the case with the calender. 

As regards cost, the capital outlay on the 500-K.W. 
generating plant, including engines, dynamos, boilers, 
condensers, steam pipes, filters, etc., and all engine room 
accessories, was £9,500. 

In addition to the above, the plant also contains a Parson's 



222 



THE MANUFACTUEE OF PAPEE 




PAPEE MILL MAOHINEEY 223 

steam turbine of 1,000 K.W., driving two continuous current 
dynamos. 

The Eihel Patent. — One of the most important improve- 
ments in connection wilh the manufacture of newspaper is the 
Eibel process, designed to increase the speed of the machine 
and to reduce the amount of suction at the vacuum box. In 
the ordinary machine the wire has usually been arranged 
to move in a horizontal plane. In some machines means 
hava^been provided for adjusting the breast-roll end of the 
wire to different elevations to provide for dealing with 
different grades of stock, but the wire has never hitherto 
been so inclined as to cause the paper stock to travel at a 




Fig. 68. — Diagram of tlie "Eibel" Process. 

speed, under the action of gravity, to equal or approxi- 
mate the speed of the wire. In all previous methods of 
working, the wire has for a considerable portion of its 
length, starting from the breast-roll, drawn the stock along 
in consequence of the wire moving much faster than the 
stock, and the stock has waved, or rippled, badly near the 
breast-roll end of the wire. This has gradually diminished 
until an equilibrium has been established and an even surface 
obtained, but not until the waving or rippling has ceased at 
some considerable distance from the breast-roll have the 
fibres become laid uniformly, and the machines have there- 
fore necessarily been run slowly to give ample time for the 
water to escape and for the fibres to lie down so as to make 
them a uniform sheet. In many cases the breast-roll has 



224 THE MANUFAOTUEE OE PAPER 

been raised 14 or 15 inches, and the stock rushes, as it were, 
downhill. 

As, during the formation of the paper, the stock and the 
wire practically do not move relatively to each other, there 
is no drag of the stock upon the wire ; consequently there is 
a more rapid and uniform drainage of the water from the 
stock, the full influence of the " shake" is made effective to 
secure uniformity in the distribution and interlocking of the 
fibres, and the regularity of the formation of the paper is 
not disturbed by waves or currents, which would otherwise 
be caused by pull of the wire upon the stock. 

This ingenious device is now working successfully in 
many paper mills. 

Machinery. — In setting out the plant necessary for a 
paper mill which is designed to produce a given quantity 
of finished paper, the manufacturer takes into consideration 
the class of paper to be made and the raw material to be 
employed. The following schedule has been prepared on 
such a basis : — 

Plant and Machinery for High-class Printings. 

Pape7\ 

High-class printings made of wood pulp and esparto, 
used alone or blended in varying proportions as 
required. Quantity, 250 tons weekly. 
Raw Material. 
Esparto ; chemical wood pulp. 
Quantity: esparto, about 200 tons; wood pulp, 150 

to 160. 
China clay and usual chemicals. 
In the estimation of materials required for the production 
of about 250 tons of paper, it is assumed that the 200 tons 
of esparto fibre will yield 90 tons bleached esparto fibre, and 



PAPEE MILL MACHINEET 225 

that the mechanical losses which take place during manu- 
facture are counterbalanced by the weight of china clay 
added to the pulp. These conditions naturally vary in 
different mills, but such variations do not affect the schedule 
of machinery. 
Unloading Sheds. 
2 steam or electric cranes for handling fibre, clay, alum, 

bleach, rosin, coal, and finished paper. 
H 3-ton weighbridge. 
1 5-cwt. platform scales. 
Steam Plant. 

6 8-ft. by 30-ft. Lancashire boilers. 
Fuel economiser. 
Feed-water pump and tank. 
Water softening apparatus. 

1 500-h.-p. main steam engine, for fibre departments 
and beater floor. 

Chemical Department. 

Hoist for clay, alum, bleach, lime, &c. 

4 causticising pans, 9 ft. diameter, 9 ft. deep. 

2 storage tanks. 

2 chalk sludge filter presses. 

2 clay-mixing vats, 6 ft. diameter, 6 ft. deep. 
1 starch mixer, 6 ft. diameter, 6 ft. deep. 

1 size boiler, 8 ft. diameter, 8 ft. deep. 

3 size storage tanks, 1,000 gallons each. 
3 bleach-mixing vats. 

3 bleach liquor settling tanks. 

2 clear bleach liquor storage tanks. 
1 alum dissolving tank. 

Recovery Department : — 
Soda. 
1 multiple effect evaporating plant. 
1 rotary furnace. 



226 THE MANUFAOTUEE OF PAPER 

4 lixiviating tanks, 2,000 gallons each. 

2 storage tanks for clear liquor from, lixiviating tanks, 

20,000 gallons capacity. 

Fibre. 
2 tanks for receiving machine backwater. 
2 Fullner's stuff catchers, or some other system of 

treating backwater. 
2 filter presses. 
Esparto Department. 

1 esparto duster. 

Travelling conveyer for cleaned esparto. 

6 Sinclair vomiting boilers, each of 3 tons capacity. 

2 measuring tanks for caustic liquor. 
4 washing engines, 15 cwt. capacity. 
6 Tower bleaching engines. 

1 press-pate. 

10 galvanised iron trucks. 
Wood Pidp Department. 

4 pulp disintegrators and pumps. 

4 Tower bleaching engines. 

4 washing tanks or drainers. 

6 galvanised iron trucks. 
Beater Floor. 

8 1,200-lbs. beating engines. 

2 Marshall refiners. 

6 galvanised iron trucks. 
Paper Machine Room. 

2 paper machines, 106 in. wide, with stuff chests, 
strainers, and engines complete. 

1 paper machine, 120 in. wide, with stuff chests, 
strainers, and engines complete. 

Patent dampers for each machine. 
Calendering Room. 

2 110- in. super calenders. 



PAPEE MILL MACHINEET 227 

2 100-in. supercalenders. 

2 6-reel cutters. 

1 200-h,-p. main steam engine. 
Finishing Room. 

Sorting tables. 

Packing press. 

Weighing machine. 
Repairs Department. 

Vsnal repair outfit, such as lathes, planing machine, 
drilling tools, etc. 

Blacksmith's shop outfit. 

Carpenter's shop outfit. 

Calender roll grinder. 
Water Supply. 

Main storage tank, 50,000 gallons capacity. 

Water pumps. 

Piping and connections to various departments. 

Bell's patent filters (if necessary). 



q2 



CHAPTEE XII 



THE DETEEIOEATION OF PAPER 



Eecent complaints about the quality of paper and the 
rapid decay of manuscripts and papers have resulted in 
arousing some interest in the subject of the durability of 
paper used for books and legal documents, and in the 
equally important question of the ink employed. The 
Society of Arts and the Library Association in England 
and the Imperial Paper Testing Institute in Germany have 
already appointed special committees of inquiry, and from 
this it is evident that the subject is one of urgent importance. 

It is sometimes argued that the lack of durability is 
due to the want of care on the part of manufacturers in 
preserving the knowledge of paper-making as handed down 
by the early pioneers, but such an argument is superficial 
and utterly erroneous. The quality of paper, in common 
with the quality of many other articles of commerce, has 
suffered because the demand for a really good high-class 
material is so small. The general public has become 
accustomed to ask for something cheap, and since the 
reduction in price is only rendered possible by the use of 
cheap raw material and less expensive methods of manu- 
facture, the paper of the present day, with certain exceptions, 
is inferior to that of fifty years ago. 

The causes which favour the deterioration of paper are 
best understood by an inquiry into the nature of the fibres 
and other materials used and the methods of manufacture 
employed. 



THE DETEEIORATION OF PAPER 229 

The Fibres Used. — Cotton and linen rags stand pre- 
eminent amongst vegetable fibres as being the most suitable 
for the production of high-class paper capable of with- 
standing the ravages of time. This arises from the fact 
that cotton and linen require the least amount of chemical 
treatment to convert them into paper pulp, since they are 
almost pure cellulose, cotton containing 98*7 per cent, of air- 
dry cellulose, and flax 90"6 per cent. The processes through 
whi<!!i the raw cotton and flax are passed for the manu- 
facture of textile goods are of the simplest character, and 
the rags themselves can be converted into paper without 
chemical treatment if necessary. As a matter of fact 
certain papers, such as the 0. W. S. and other drawing 
papers, are manufactured from rags without the aid of 
caustic soda, bleach, or chemicals. The rags are carefully 
selected, boiled for a long time in plain water, broken up 
and beaten into pulp, and made up into sheets by purely 
mechanical methods. 

The liability of papers to decay, in respect of the fibrous 
composition, is almost in direct proportion to the severity 
of the chemical treatment necessary to convert the raw 
material into cellulose, and the extent of the deviation of 
the fibre from pure cellulose is a measure of the degradation 
which is to be expected. The behaviour of the fibres 
towards caustic soda or any similar hydrolytic agent serves 
to distinguish the fibres of maximum durability from those 
of lesser resistance. It may be noted that in the former 
the raw materials, viz., cotton, linen, hemp, ramie, etc., 
contain a high percentage of pure cellulose, while in the 
latter the percentage of cellulose is very much lower, 
such fibres as esparto, straw, wood, bamboo, etc., giving 
only 40 — 50 per cent, of cellulose. The two extremes are 
represented by pure cotton rag and mechanical wood 
pulp. Other things being equal, the decay which may 



230 THE MANUFACTUEE OF PAPER 

take place in papers containing the fibre only, without the 
admixture of size or chemicals, may be considered as one 
of oxidation, which takes place slowly in cotton, and much 
more rapidly with mechanical wood pulp. Experimental 
evidence of this oxidation is afforded when thin sheets 
of paper made from these materials are exposed to a 
temperature of 100° to 110° C. in an air oven. The cotton 
paper is but little affected, while the mechanical wood pulp 
paper soon falls to pieces. 

The order of durability of various papers in relation to 
the fibrous constituents may be exjjressed thus : (1) rag 
cellulose ; (2) chemical wood cellulose ; (3) esparto, straw, 
and bamboo celluloses ; (4) mechanical wood j)ulp. The 
rate and extent of oxidation is approximately shown by the 
effect of heat as described. The differences between the 
celluloses are also shown by heating strips of various papers 
in a weak solution of aniline sulphate, which has no effect 
on wood or rag cellulose, dyes esparto and straw a pinkish 
colour, and imparts a strong yellow colour to mechanical 
wood pulp and jute. 

Physical Qualities. — The permanence of a paper depends 
not only upon the purity of the fibrous constituents and the 
freedom from chemicals likely to bring about deterioration, 
but also upon the general physical properties of the paper 
itself. Other things being equal, the more resistant a paper 
is to rough usage the longer will it last. The reason why 
rag papers are so permanent is that not only is the chemical 
condition of the cellulose of the highest order, but the 
physical structure of the fibre is such that the strength of 
the finished paper is also a maximum. 

The methods of manufacture may be modified to almost 
any extent, giving on the one hand a paper of extraordinary 
toughness, or on the other hand a paper which falls to 
pieces after a very short time. Thus a strong bank-note 



THE DETEEIOEATION OF PAPER 231 

paper may be crumpled up between the fingers three or four 
hundred times without tearing, while an imitation art paper 
is broken up when crumpled three or four times. 

A thorough study of the physical qualities of a paper is 
therefore necessary to an appreciation of the conditions for 
durability. The physical structure of the fibre, the modifi- 
cations produced in it by beating, the effect of drying, sizing, 
and glazing upon the strength and elasticity of the finished 
paper, are some of the factors which need to be considered. 

Strength. — The strength of a paper as measured by the 
tensile strain required to fracture a strip of given width, and 
the percentage of elongation which the paper undergoes when 
submitted to tension, are properties of the utmost import- 
ance. The elasticity, that is, the amount of stretch under 
tension, has not received the attention from paper-makers 
that it deserves. If two papers of equal tensile strength 
differ in elasticity, it may be taken for granted that the 
paper showing a greater percentage of elongation under 
tension is the better of the two. 

The strength of a paper, as already indicated, is greatly 
influenced by the conditions of manufacture. This has 
been explained in the chapter devoted to the subject 
of beating, and other examples are briefly given in the 
following paragraphs. 

Bulk. — The manufacture during recent years of light 
bulky papers for book production has accentuated the 
problem in a marked degree, and the factor of hulk as one 
of the causes of deterioration is therefore a comparatively 
new one. It is interesting to notice that the rapid destruc- 
tion of such books by frequent use is in no way related to 
the chemical purity of the cellulose of which it is composed, 
or to the influence of any chemical substance associated 
with the fibre. It is purely a mechanical question, to be 
explained by reference to the process of manufacture. 



232 



THE MANUFAOTUEE OE PAPEE 



This paper is made from esparto entirely, or from a 
mixture of esparto and wood pulp. The pulp is beaten 
quickly, and for as short a time as possible, little or no 
china clay being added, and only a very small percentage 
of rosin size. The wet sheet of paper is submitted to very 
light pressure at the press rolls, and the bulky nature is 
preserved by omitting the ordinary methods of calendering. 

The paper thus produced consists of fibres which are but 
little felted together. The physical condition and structure 
of the paper are readily noticeable to the eye, and when these 
peculiarities are reduced to numerical terms the effect of 
the conditions of manufacture is strikingly displayed. 

The effect of this special treatment is best seen by con- 
trasting the bulky esparto featherweight paper with the 
normal magazine paper made from esparto. In the latter 
case a smoother, heavier, stronger sheet of paper is made 
from identically the same raw material. But the pulp is 
beaten for a longer period, while mineral matter and size 
are added in suitable proportions. The press rolls and 
calenders are used to the fullest extent. 

The difference between these two papers, both consisting, 
as they do, of pure esparto with a small proportion of ash 
may be emphasised by comparing the analysis by iveight with 
analysis hj volume. Thetwo papers in question when analysed 
by weight proved to have the following composition : — 





Parts by Weiglit. 




Featherweight. 


Ordinary. 


Esparto fibre 
Ash, etc. 


96-0 

4-0 

100-0 


95-4 

4-6 

100-0 



THE DETEEIO RATION OF PAPEE 



233 



But if the papers are compared in terms of the composition 
by volume, it will be found that the featherweight contains 
a large amount of air space. 





Composition by Volume. 




Featherweight. 


Ordinary. 




Esparto fibre 


28-0 


65-5 




Asli, etc. 


0-7 


1-8 




Air space 


11-3 


32-7 






100-0 


100-0 





In other words, the conditions of manufacture for the 
bulky paper are such that the fibres are as far apart from 
one another as possible, and the cohesion of fibre to fibre 
is reduced to a minimum. 

"While paper of this description is agreeable to the printer, 
and probably to the general reading public, yet its strength 
and physical qualities, from the point of view of resistance 
to wear and tear, are of the lowest order. It is very difficult 
to rebind books made from it, which is not altogether to be 
wondered at, seeing that the bookbinder's stitches can 
hardly be expected to hold together sheets containing 60 to 70 
per cent, of air space. 

This concrete case emphasises the necessity for including 
in a schedule of standards of quality a classification of 
papers according to strength and bulk. 

Surface. — The introduction of new methods of printing 
has brought about some changes in the process of glazing 
and finishing paper which are not altogether favourable to 
the manufacture of a sheet having maximum qualities of 
strength and elasticity, two conditions which are essential 



234 THE MANUFACTUEE OF PAPEE 

to permanence. In other words, the very high finish and 
surface imparted to paper by plate-glazing, supercalendering, 
water finish, and other devices of a similar character is 
carried to excess. 

All papers are improved in strength by glazing up to a 
certain point, but over-glazing crushes the paper, renders 
it brittle and liable to crack. Unfortunately, the maximum 
strength of a paper is generally reached before the maximum 
of finish, with the result that the former is frequently 
sacrificed to the latter. The usual result of glazing is found 
in an increase of 8 to 10 per cent, in the tensile strength, but 
a diminution of elasticity to the extent of 8 to 10 per cent. 
With supercalendered magazine papers, the high surface 
is imparted for the sake of the illustrations which are pro- 
duced by methods requiring it. The addition of consider- 
able quantities of clay or mineral substances improves the 
finish, so that the question of the relation of glazing to 
strength, surface, and loading is one which affects the 
subject of deterioration of paper very materially. With 
writing paper the false standard of an " attractive " appear- 
ance is almost universally accepted by the public as the 
basis of purchase without any reference to actual quality. 

]\lineral Substances. — China clay, sulphate of lime, agalite 
and other inert mineral substances are important factors 
in lowering the quality of paper, not so much in promoting 
the actual deterioration of paper by any chemical reaction 
with the fibres, as in making the paper less capable of 
resistance to the influence of atmospheric conditions and 
ordinary usage. Clay in small, well-defined quantities 
serves a useful purpose, if added to some papers, because 
it favours the production of a smooth surface, but when 
the combination of mineral substances is carried to an 
extreme, then the result from the point of view of per- 
manence is disastrous. This is well recognised by all 



THE DETEEIOEATION OF PAPER 23o 

paper-makers, and in Germany the limits of the amount of 
clay or loading in high-grade paper have been rigidly fixed. 
In the case of imitation art paper, which contains 25 to 
30 per cent, of its weight of clay, the strength and resist- 
ance of the sheet is reduced to a minimum. The paper 
falls to pieces if slightly damped, the felting power of the 
fibres being rendered of no effect owing to the weakening 
influence of excessive mineral matter. This paper is used 
chiefly for catalogues, programmes, circulars, and printed 
matter of a temporary and evanescent character, and so 
long as it is confined to such objects it serves a useful pur- 
pose, being cheap, and suitable for the production of 
illustrations by means of the half-tone process ; but its 
lasting qualities are of the lowest order. The addition of 
10 per cent, of any mineral substance must be regarded as 
the maximum allowance for papers intended for permanent 
and frequent use. 

Coating Material. — The ingenious method for producing 
an absolutely even surface on paper by the use of a mix- 
ture of clay or other mineral substance and an adhesive 
like glue or casein brushed on to the surface of the paper, 
is responsible for many of the complaints about the papers 
of the present day. 

The sole merit of this substance is the facility with which 
half-tone process blocks can be utilised for the purpose of 
picture production. Beyond this, nothing can be said. 
The paper is brittle, susceptible to the least suspicion of 
dampness, with a high polish which in artificial light pro- 
duces fatigue of the reader's eye very quickly, heavy to 
handle, and liable to fall to pieces when bound up in book 
form. 

As the fibrous material is completely covered by mineral 
substances, it is frequently considered of secondary import- 
ance, with the result that the "value" of the paper is 



236 



THE MANUFACTURE OF PAPER 



judged entirely by the surface coating, with little regard to 
the nature of the body paper. In such cases, with an 
inferior body paper, the pages of a book very quickly 
discolour, and the letterpress becomes blurred. 

Analysis of a Typical Art Paper. 



- 


Per Cent, by 
Weight. 


- 


Volume 

Composition 

per Cent. 


Fibre 


77-5 


Fibre . 


68-3 


Ash, etc. . 


22-5 


Ash 


12-0 






Air space 


19-7 




100-0 




100-0 



Rosin. — The presence of an excess o£ rosin is a well- 
known factor in the disintegration of the paper, even when 
the fibrous composition is of the highest order. The 
decomposition is largely due to the action of light, many 
experiments having been made by Herzberg and others to 
determine the nature of the reactions taking place. One 
of the chief alterations is the change brought about in the 
ink-resisting qualities of the paper. 

The actual character of the chemical reactions as far as 
the effect on the fibre is concerned is not accurately 
known. The degradation of a hard-sized rosin paper by 
exposure to strong sunlight, for example, is probably due 
to the alteration in the rosin size, and not to any material 
change in the cellulose. It is hardly conceivable that in a 
pure rag paper sized with rosin and yielding readily to ink 
penetration, after about one year's exposure to light, the 
cellulose itself had undergone any chemical changes capable 
of detection. 



THE DETEEIOEATION OF PAPEE 237 

Gelatine. — Papers properly sized with gelatine are prefer- 
able to those sized with rosin for the majority of books and 
documents preserved under normal circumstances. But 
the nature of a tub-sized paper may be, and often is, 
greatly altered by unusual climatic conditions. In hot, 
damp countries papers are quickly ruined, and high-class 
drawing papers sized with gelatine often rendered useless. 
The change is scarcely visible on the clean paper, and is 
only- observed when the paper is used for water-colour 
work, the colour appearing blotchy in various parts of the 
sheet where the gelatine has been decomposed by the 
united action of heat and damp. 

The artist is frequently compelled in such cases to put a 
layer of heavy white colour on the sheet of paper before 
proceeding to paint the picture. 

The storage of books under favourable conditions has a 
great deal to do with the permanence of the paper, and 
the degradation of a paper in relation to the tub-sizing 
qualities is much hastened by the presence of moisture 
in the air. 

Starch.— The same is true of starch, which is largely 
employed as a binding or sizing material in paper. The 
degradation of gelatine, starch, and similar nitrogenous 
substances is due to the action of organisms, and the 
following experiments, suggested by Cross, are interesting 
in this connection. 

If strips of paper are put into stoppered bottles with a 
small quantity of warm water and kept at a temperature 
of about 80° F., fungus growths will be noticed on some of 
them after the lapse of fourteen days. Eag papers sized 
with gelatine will show micro-organisms of all kinds. A 
pure cellulose paper, like filter paper, will not produce any 
such effects. The result in the first case is due to the 
nitrogenous substance, viz., the gelatine used in sizing, 



238 THE MANUFACTUEE OF PAPER 

since the two papers are identical as far as the cellulose 
fibres are concerned. High-class wood pulp papers, unless 
sized with gelatine, would not show similar results. The 
action of the organisms upon the nitrogenous material by a 
process of hydrolysis is in the direction of the production 
of soluble compounds allied to the starch sugars capable of 
being assimilated by organisms. 

The cellulose of esparto and straw are readily attacked, 
and it is on this account that the tissues of the various 
straws are digested more or less when eaten by animals. 
It is for this reason that the celluloses from straw and 
esparto are inferior to the cotton cellulose in producing a 
paper likely to be permanent. 

Chemical Residues. — The necessity for manufacturing a 
pure cellulose half-stuff is fully recognised by paper- 
makers. This was not the case in the early days of the 
manufacture of wood pulp, for it is a matter of common 
experience that many of the books printed on wood pulp 
paper between 1870 and 1880 are in a hopeless condition, 
and it is quite easy to find books and periodicals of that 
date the pages of which crumble to dust when handled. 
This serious defect has been proved to be due to the pre- 
sence of traces of chemicals used in manufacture which 
have not been thoroughly removed from the pulp. 

The precautions necessary in bleaching pulp by means 
of chloride of lime, in order to prevent (1) any action 
between the fibre and the calcium hypochlorite, ;2) the 
presence of residual chlorine or soluble compounds derived 
from it, and (3) the presence of by-products arising from 
the use of an antichlor, are also well known to paper 
makers. The subject has been closely studied by chemists, 
who have shown that the deterioration of many modern 
papers may be ascribed to carelessness in bleaching. 

The questions relating to the chemical residues of paper 



THE DETEEIOEATION OF PAPEE 239 

can only be adequately dealt with by a discussion of actual 
cases which arise from time to time. There are certain 
conditions in manufacture, common to all papers, which 
may give rise to the presence of chemical residues, of 
which two have already been mentioned. 

The acidity of papers is frequently quoted as aa instance. 
It is true that the presence of free acid in a paper is most 
undesirable, as it seriously attacks the cellulose, converting 
it intp an oxidised form. This in course of time renders 
the paper so brittle as to destroy its fibrous character. 

The change is brought about by the acid, which itself 
suffers no material alteration, so that the process of deterio- 
ration is continued almost indefinitely until the cellulose 
is completely oxidised. Most papers, however, show an acid 
reaction when tested with litmus, the usual reagent employed 
by those not familiar with the proper methods of testing 
paper. All papers which have been treated with an excess 
of alum for sizing purposes would show an acid reaction 
with litmus without necessarily containing any free acid. 

The presence of iron is undesirable, particularly in photo- 
graphic papers, and since cellulose has a remarkable affinity 
for iron, the conditions of manufacture which tend to leave 
iron in the pulp have to be taken into consideration. The 
presence of minute quantities of iron in the form of 
impurities must not be confused with the presence of iron in 
large quantities derived from the toning and colouring of 
paper by means of iron salts. 

The fading of colour is frequently observed when coloured 
papers are tested on boxboards, particularly those made of 
straw. This fading may often be traced to the presence of 
alkali in the straw board which has not been completely 
removed in the process of manufacture. 

The blurring of letterpress is a defect which often occurs 
with printing papers made of chemical wood pulp. The oil 



240 THE MANUFACTUEE OF PAPEE 

in the ink seems to separate out on either side of the letter, 
producing a discoloration. In such cases the paper itself 
frequently exhibits an unpleasant smell. 

These defects are usually determined by the presence of 
traces of sulphur compounds in the paper resulting from 
incomplete washing of the pulp in manufacture. The 
presence of sulphur compounds sometimes associates itself 
with papers which have been coloured by means of ultra- 
marine, which in presence of alum is slightly decomposed 
by the heat of the drying cylinders. 

Some knowledge of the effect of chemical residues in 
paper is important, not only in regard to the deterioration 
which takes place in the fibre itself, but also in relation to 
the fading of the ink which is used. The subject of the ink 
has received much attention from chemists on account of 
the serious difficulties which have been experienced by State 
departments in various countries. 

The United States Department of Agriculture have devised 
certain methods for ascertaining the suitability of stamping 
ink used by the Government and suggest the qualities 
desirable in such an ink. The ink, first of all, must produce 
an indelible cancellation ; that is, it must be relatively 
indelible as compared with the ink used for printing the 
postage stamps. The post-mark made with the ink must 
dry quickly in order that the mail matter may be handled 
immediately without any blurring or smearing of the post- 
mark. 

Both this property and the iDroperty of the indelibility 
involve the question of the rate at which the ink penetrates 
or is absorbed by the fibre of the paper. A satisfactory ink 
does not harden or form a crust on the ink-pad on exposure 
to air. There must be no deposition of solid matter on the 
bottom of the vessel in which the ink is stored, and the pig- 
ments on which the indelibility of the ink depends, if 



THE DETERIOEATION OF PAPER 241 

insoluble, must not settle out in such a way as to make it 
possible to pour off from the top of the container a portion 
of the ink which contains little or none of the insoluble 
pigment or pigments. 

Colour. — If the subject of deterioration of paper is to be 
considered in its broadest sense as including changes of any- 
kind, the fading of colour must be taken into account. The 
use of aniline dyes which are not fast to light results in a 
loss <Tf colour in paper just as with textiles, and the fading 
may be regarded as a function of the dye and not as arising 
from its combination with the paper. 

The gradual fading of some dyes, however, and of many 
water-colour pigments may be traced to the presence of 
residual chemicals in the jjaper and to the presence of 
moisture in an atmosphere impregnated with gaseous or 
suspended impurities. In fact the latter is a greater enemy 
to permanence of colour than light, since it has been proved 
by experiment that most colours do not fade when exposed 
to light in a vacuum. The oxygen of the air in combination 
with the moisture present is the principal agent in bringing 
about such changes. The dulling of bronze, or imitation 
gold leaf, on cover papers is a practical illustration of this, 
though this can hardly be quoted as an instance of actual 
deterioration of the paper. 

The maintenance of the original colour can only be 
assured by the careful selection of pure fibrous material, 
the use of fast dyes, and the preservation of the book or 
painting from the conditions which fayour the fading as 
described above. For common papers such precautions 
become impossible, but for water-colour drawings and 
valuable papers they are essential. 

The demand for an abnormally white paper is indirectly 
the cause of deterioration in colour, but in this case the 
ultimate effect is not a fading but a discoloration of white 



242 THE MANUFACTUEE OE PAPER 

to a more or less distinct yellow or brown colour, due to 
changes in the fibre which may often be traced to excessive 
bleaching. In this case the fading of colour is directly due 
to deterioration of the paper itself, and may occur in 
celluloses of the best type. With lower-grade papers con- 
taining mechanical wood pulp the degradation of colour 
and fibre is inevitable. 

Air and Moisture. — The exact effects produced on paper 
freely exposed, or in books as ordinarily stored, depend upon 
the condition of the atmosphere. Pure air has little or no 
action upon paper, cellulose being a remarkably inert sub- 
stance, and even in impure mechanical wood pulp, if merely 
exposed to pure dry air, the signs of decay would be delayed 
considerably. The combined action of air and moisture is 
of a more vigorous character in promoting oxidation changes 
in the fibres, or a dissociation of the sizing and other 
chemical ingredients of the paper. The presence of 
moisture is, indeed, absolutely essential for the reaction of 
some substances upon one another, and it is easy to show 
that certain chemical compounds can be left in ultimate 
contact, if absolutely dry, for a lengthened period without 
reacting, but the addition of a little moisture at once pro- 
duces chemical union. This may be shown by a simple 
experiment. 

Thus a piece of coloured paper which may be bleached 
immediately if suspended in an atmosphere of ordinary 
chlorine gas will remain unbleached for several hours if 
first thoroughly dried in an oven and exposed to dry gas. 

In the case of books and papers, these conditions which 
promote slow disintegration are aggravated by the presence 
of impurities in the air, such as the vapours of burning gas, 
the traces of acidity in the atmosphere of large manu- 
facturing towns, the excessive dampness and perhaps heat 
of a climate favouring the growth of organisms. All these 



THE DETERIORATION OF PAPER 243 

factors are of varying degrees in different places, so that 
the deterioration of papers does not proceed in the same 
measure and at the same rate everywhere. 

Moisture. — It may not be out of place to discuss some 
important relations between moisture and the physical 
qualities of a sheet of paper. A paper in its normal con- 
dition always contains a certain proportion of water as one 
of its ingredients, and the presence of this moisture has 
mucTi to do with the strength, elasticity, and use of the 
paper, the absence of moisture giving rise to defects and 
troubles in the use of the paper which to a certain extent 
lower its commercial value and deteriorate it, though not 
perhaps in the sense of permanent degradation of quality. 

One trouble frequently experienced by stationers and 
others is that known as wavy edges. The edges of a stack 
containing sheets of paper piled upon one another frequently 
twist and curl, producing what are known as wavy edges. 
This arises from the fact that the paper when manufactured 
was deficient in natural moisture, and that when stacked it 
has gradually absorbed moisture, which is taken up first by 
the edges exposed to the air. This causes unequal ex]3ansion 
of the fibres with the production of the so-called wavy edges. 
The only remedy in such cases is the free exposure of the 
sheets before printing, so that the m.oisture is absorbed 
equally all over the sheet. The cracked edges of envelopes 
may be explained by reference to the same conditions. 
The paper is worked up into envelopes in an over-dry 
condition, and the fibres, being somewhat brittle, readily 
break apart from one another. If the paper is kept in 
stock for some time before use this defect can be very 
largely remedied. 

With supercalendered papers it is only possible to obtain 
the best results by allowing the jDaper to stand for several 
days after making before it is glazed. 

R 2 



.244 THE MANUFACTUEE OE PAPER 

It is evident from these few examples that many of the 
troubles experienced by printers are due to the fact that 
orders for paper are frequently accompanied by an instruc- 
tion for immediate delivery, under which circumstances it is 
impossible to obtain the best results. The expansion of 
papers used for lithography, and the bad register frequently 
seen in colour work, may be explained by reference to the 
behaviour of the individual fibres towards moisture. The 
expansion is usually greater in one direction of the paper 
than in the direction at right angles to it, and this is due to 
the fact that fibres have a greater ratio of expansion in the 
diameter than in the length. 

The behaviour of papers when damped is a peculiarity 
well known to paper-makers and printers. For certain 
purposes it is desirable that paper should not show any 
material alteration when damped, since any expansion of 
the sheet is liable to throw the printing out of " register." 
The liability of papers to such stretch or expansion is 
largely minimised by careful manipulation of the pulp 
during the process of beating, and also by a proper regula- 
tion of the web of paper as it passes from the wet end of 
the paper machine over the drying cylinders to the 
calenders. The paper which fulfils the necessary qualifica- 
tions as to a minimum stretch is prepared from pulp which 
has not been beaten for too long a period, so that the pulp 
obtained is fairly light and bulky. By this means the 
expansion of the fibres takes place in the sheet itself with- 
out making any material alteration in its size. That is to 
say, as the sheet of paper is fairly open, there is sufficient 
room for expansion, which thus takes place with the least 
alteration of the total area of the sheet. The paper which 
is allowed to shrink on the machine during the process of 
drying, without undue tension, usually exhibits a minimum 
amount of expansion subsequently in printing. 



THE DETERIOEATION OF PAPER 245 

It is important to notice that the expansion of paper is 
different for the two directions, that is for the machine and 
cross directions. 

This arises from the fact that in the machine-made paper 
the greater proportion of the fibres point in the direction of the 
machine while the paper is being made. In consequence of 
this the expansion of the paper is greatest in what is known as 
the cross direction of the paper, that is, in the direction at 
right angles to the flow of the pulp along the machine wire. 

This is to be explained by reference to the behaviour of 
fibres when damped or brought into contact with an excess 
of water. The question of the exact changes in the dimen- 
sions of a fibre due to absorption of water has been dealt 
with in an interesting manner by Hohnel. He points out 
that the well-known peculiarity of the shrinkage of ropes 
which have been lying in the v/ater can be explained by an 
examination of the behaviour of the single fibres. He 
relates in detail the experiment which can be carried out 
for the exact observation of the fibres when in contact with 
water. A dry fibre when soaked in water appears to become 
20 to 30 per cent, greater in diameter, whereas in length it 
is usually only increased by one-tenth per cent. 

The method adopted by Hohnel was to place a fibre of 
convenient length on a glass slip down the centre of which 
was a fine narrow groove capable of holding water, so that 
the fibre could be wetted. Over the fibre was a cover glass 
with a small scale marked on it. The loose end of the 
fibres passed over a small roller and was stretched by a 
light weight. The movements of the fibre were measured 
by means of an eye-piece micrometer. 

In this way it is possible to determine alterations in 
length to within 0*005 per cent., and this variation can be 
directly seen under the microscope. 

Hohnel observes in his account of the experiments that 



246 



THE MANUFAOTUEE OF PAPEE 



all fibres become thicker when wetted, that vegetable fibres 
are more susceptible than animal fibres. 

Animal fibres expand about 10 to 14 per cent, in diameter, 
but vegetable fibres as much as 20 per cent,, as shown in the 
following table : — 



Animal Fibre. 


Per Cent. 


Vegetable Fibre. 


Per Cent. 


Human hair . 
Angora wool . 
Alpaca wool . 
Tussah silk . 


10-67 
10-2 
13-7 
11-0 


New Zealand flax 
Aloe hemp 
Hemp 
Cotton 


20-0 
25-8 
22-7 
27-5 



The reverse is the case when the expansion of the fibres 
in regard to length is considered, since animal fibres expand 
0'60 to I'OO per cent, of their length, and vegetable fibres 
only 0*05 to 0"10 per cent. 

The maximum amount of expansion in the case of the 
vegetable fibres is obtained by gently breathing upon them 
rather than by the use of an excess of water. 

These figures are important as explaining many of the 
peculiar characteristics of vegetable and animal fibres. 
Advantage is taken of the greater expansion of the latter 
in the manufacture of instruments for the measurement 
of moisture, such as the hair hygrometer, in which t)ie 
elongation of a stretched hair registers the variation in 
the moisture of the atmosphere. 

Quality of Book Papers. — The Committee of the Society 
of Arts in dealing with the evidence as to the permanence 
of finished papers suggest the following classification as 
indicating the desired standards of quality: — 

(A) Classification as to Fibres. 

A. Cotton, flax, and hemj). 

B. Wood celluloses, (a) sulphite jDrocess, and (b) soda and 

sulphate process. 



THE DETEEIOEATION OF PAPER 247 

C. Esparto and straw celluloses. 

D. Mechanical wood pulp. 

The Committee find little fault with the Principles which 
govern the trade in the manufacture of high-class papers, 
and limit the result of their investigation to the suggestion 
of a normal standard of quality for book papers required 
in documents of importance according to the following 
schedule : — 

Fji>res. — Not less than 70 per cent, of fibres of Class A. 

Sizing. — Not more than 2 jDer cent, rosin, and finished 
with the normal acidity of pure alum. 

Loading. — Not more than 10 per cent, total mineral 
matter (ash). 

With regard to written documents, it must be evident 
that the proper materials are those of Class A, and that the 
paper should be pure, sized with gelatine and not with 
rosin. All niiitations of high-class writing papers, which 
are in fact merely disguised printing papers, should be 
carefully avoided. 

These recommendations are good as far as they go, but 
in order to establish the proper standards of quality some 
specifications must be laid down with regard to the strength 
of the paper and its physical properties, together with a 
reference to the use for which the paper is intended. The 
physical condition of the paper itself apart from the nature 
of the fibre has much to do with its resistance to wear and 
tear, and this is easily proved by comparing modern book 
papers made from esparto with book papers of an earlier 
date made from the same material. 

The only official schedule of requirements in relation to 
public documents is that issued by the Stationery Office. 

The details set out relate chiefly to questions of weight and 
strength, the limits being expressed in definite form and not 
allowing much margin for variation in respect of strength 



248 THE MANUFACTUEE OF PAPER 

or fibrous constituents. Mechanical wood pulp is excluded 
in all papers except common material as stated in the 
schedule. The papers required for stock are divided into 
twelve classes. In each class the trade names of various 
sized papers are given, the size of the sheet and the weight 
of the ream, and, where required, any special characteristics 
are set out. The schedule is as follows : — 

Class 1. Hand-made or Mould-made. 

General Specification. — Hand-made or mould-made. 
Animal tub-sized. ("Hand-made" or "Mould-made" to be 
marked on the wrapper.) 

Where special water-marking is required mould will be 
supplied by the Stationery Office for those papers made by 
hand. 

Class 2. Writings, Air-dried. 

General Specification. — Plate rolled. Machine made. 
Animal tub-sized. Air-dried. (Must bear ink after 
erasure.) 

Note. — The mean breaking strain and mean stretch 
required are given for each paper. The figures represent 
the mean of the results obtained for both directions of the 
sheet, and are calculated on a strip of paper five-eighths of 
an inch wide and having a free length of seven inches 
between the clips. 

Class 3. Writings, Ordinary. 

General Specification. — Eolled. Machine-made. Animal 
tub-sized. 

Class 4. JVritings, Coloured. 

SjJecification. — Highly rolled. Machine-made. Animal 
tub-sized. 



THE DETEEIOEATION OF PAPEE 249 

Class 5. Blotting Papers. 
Specification. — All rag. Machine-made. Free from 
loading. 

Class 6. Printing and Lithographic Papers. 

General Specification. — Eolled. Machine-made. Engine- 
sized. Loading not to exceed 15 per cent. 

Class 7. Coloured Printings. 

GTneral Specification. — Eolled. Machine-made. Engine- 
sized. 

Class 8. Copying and Tissue Papers. 

Specification. — Machine-made. Free from loading. 
(Copying pa23ers are required to give three good copies.) 

Class 9. Brown Papers, Air-dried. 

Specification. — Air-dried. Machine-made. 

Note. — The mean breaking strain and mean stretch 
required are given for each paper. The figures represent 
the mean of the results obtained for both directions of the 
sheet, and are calculated on a strip of paper two inches 
wide and having a free length of seven inches between the 
clips. 

In the case of papers indicating a larger breaking strain 
than the minimum required, a proportional increase in the 
stretch must also be shown. 

Class 10. Broivn Paper, Cylinder -dried. 

General Specification. — Machine-made. 

Note. — The mean breaking strain required is given for 
each paper. The figures represent the mean of the results 
obtained for both directions of the sheet, and are calculated 
on a strip of paper two inches wide and having a free length 
of seven inches between the clips. 



250 THE MANUFACTUEE OF PAPER 

Class 11. Smallhands. 
General Specification. — Machine-made. Engine-sized. 

Class 12. Buff Papers. 

Specification. — Highly finished both sides. Machine-made. 
Hard engine- sized. 

Mechanical wood pulp must not be used in the manufac- 
ture of any papers, with the exception of engine- sized 
coloured printings, and buff papers, where an addition up 
to 25 per cent, will be allowed. 

All animal tub-sized papers are required to be as far as 
possible free from earthy matter; and, except where 
specially stated, the amount of loading added to other papers 
must not exceed 6 ]3er cent. 

When sulphite or soda pulps are used, either separately 
or conjointly, in the manufacture of printing papers, the 
quantity of neither material shall separately exceed 50 per 
cent. 

The most complete specification as to the requirements 
for standard papers is that published by the Paper Testing 
Institute in Germany, and used as the basis of most con- 
tracts, at least for public and official documents. 

Standards of Quality in Germany. — The classification of 
papers according to the raw materials used and the nature of 
the finished paper is very complete. The classification is 
made under three headings : {A) Raw Material; (B) 
Strength; (C) Uses. 

(A) Classification according to Material. 

(1) Paper made from rags only (linen, hemp, and cotton). 

(2) Paper made from rags with a maximum of 25 per 
cent, of cellulose from wood, straw, esparto, manila, etc., but 
free from mechanical wood pulp. 



THE DETEEIOEATION OF PAPER 



251 



(3) Paper made from any fibrous material, but free from 
mechanical wood pulp. 

(4) Paper of any fibrous material. 



(B) Classification 


according to 


Strength. 




Class 


1. 


2. 


3. 


4. 


5. 


6. 


Mean tearing length in 
me^es .... 

Elasticity per cent. 

Eesistance to folding 
(Schoppers' method, 
number of foldings) . 


1,000 
4 

190 


5,000 
3-0 

190 


■1,000 
3 

80 


3,000 
2-5 

■10 


2,000 
2 

20 


1,000 
1-5 

3 



The tests for tearing length, resistance to folding, elas- 
ticity, etc., are made in air showing relative humidity of 
65 per cent. The calculations for tearing length are made 
on strips of paper dried at 100° C. 



(C) Classification according to Use. 





Uses. 


Fibre. 


Stcengtli. 


Size of Sheets. 


Weight of 


X 








Glass. 


Class. 


Cm. 


1,000 


1 Sq. 












Sheets. 


Metre. 












Kg. 


Grms. 


1 


Writing papers for im- 














portant documents . 


1 


1 


33 X 42 


15 


— 




Paper for State docu- 














ments 


1 


1 


26-5 X 42 


12 


— 


2 


Paper for registers, ac- 
count books, and 
ledgers — 














(«) First quality . 


1 


2 


33 X 42 


14 


— 




(&) Second quality 


1 


3 


33 X 42 


13 


— 


3 


Documents intended to 
be preserved longer 
than ten years — 














(rt) Foolscap paper 


2 


3 


33 X 42 


13 


— 




Letter paper 














(quarto size) 


2 


3 


26-5 X 42 


10-4 


— 



252 THE MANUFAOTUEE OF PAPER 

(C) Classification according to Use — continued. 





Uses. 


Fibre. 


Strengfli. 


Size of Sheets. 


Weight of 


m 






Q 


Class. 


Class. 


Cm. 


1,000 


1 Sq. 












Sheets. 


Metre. 












Kg. 


Grms. 




Documents intended to 
be preserved longer 
than ten years — ctm- 
tiimed. 
Letter paper 














(octavo size) 


2 


3 


26-5 X 21 


5-2 


— . 




Duplicating paper . 


2 


3 


33 X 42 


7 


— 




(&) ffi c i a 1 writing 














paper 


2 


4 


33 X 42 


13 


— 


4 


Paper for documents of 
lesser importance — 














(«) Foolscap paper 


3 


— 


33 X 42 


12 


— 




Letter paper 














(quarto size) 


3 


— 


26-5 X 42 


9-6 


— 




Letter paper 














(octavo size) 


3 


— 


26-5 X 21 


4-8 


— 




(^^) Official writing 














paper 


3 


4 


33 X 42 


12 


— 


5 


Envelopes and wrap- 
pers — 














(<•/) First quality . 


— 


3 


— 


— 


— 




(Z*) Second quality 


— 


5 


— 


— 


— 


6 


Writing paper of me- 














dium quality . 


— 


5—6 


— 


— 


— 


7 


Covers for documents — 
(a) That required for 














frequent use . 


1 


Tearing 

length 

2,500 

Elasticity 

3-5 % 


36 X 47 


81-2 


480 




(&) For other purposes 


3 


Tearing 

length 

2,500 

Elasticity 

2-5% 


36 X 47 


42-3 


250 


8 


Printing paper — 

(a) For important 














printed matter 


1 


4 


— 


. — 


— 




(b) For less important 














printed matter 


3 


4 


— 


— 


— 




(c) For common use . 


— 


5—6 


~ 







CHAPTER XIII 

• BIBLIOGRAPHY 

ANALYSIS, TECHNOLOGY, ETC. 

Abel, Dr. E. Hypochlorite und electrische Bleiche. Halle, 
1905. 

Arabol Manufacturing Co. Theory and Practice of the Sizing of 
Paper. New York, 8°, 1895. 

Behrens, H. — Anleitung zur mikrochemischen Analyse der 
wichtigsten Verbindungen. Heft 2. Die wichtigsten Faserstofle. 
Hamburg und Leipzig, 1896. 

Beveridge, J. — Paper-makers' Pocket Book. London, sm. 8°, 
1901. 

BouRDiLLAT, E. Die Entfarbung und das Bleichen der Hadern. 
Weimar, 1867. 

CoRPUT, E. Van den. — De la fabrication du papier an point de vue 
de la technologie chimique. 2e ed. Paris, 8°, 1861. 

Cross, C. F. and Bevan, E. J. — A Text-book of Paper-making. 
London, sm. 8°, 1888. 

Ditto, 2nd edition. 1900. 
Ditto, 3rd edition. 1907. 

Cross and Bevan. — Manuel de la fabrication du papier. Traduit 
de la 2e edition Anglaise. ParL. Desmarest. 1902. 

Cross, Bevan, Beadle and Sindall. — The C.B.S. Units : a Book 
on Paper Testing. 1904. 

Deterioration of Paper. — Society of Arts Eeport. 1898. 

Engelhardt, B. Hypochlorite und electrische Bleiche (Tech- 
nisch-Constructiver Teil). Halle, 1904. 

Engels, J. A. — IJeber Papier und einige andere Gegenstande der 
Technologie und Industrie. Duishurg, sm. 8°, 1808. 

Englander. — Technologie der Papier fabrikation. Lehrbuch fur 
Spezialkurse an Handel sfachschulen u. fachlich. Fortbildungsschulen 
sowie Lehrbehelf 7,vtm. Selbgtstijdium, 1906. 



254 THE MANUFACTUEE OF PAPEE 

Erfurt, J. Farben des Papierstofls. Mit 145 Proben in Stoffge- 
farbten Papiere, 2te Aufl. Berlin, 8°, 1900. 

Erfurt, J. The Dyeing of Paper Pulp ; from the 2nd German 
edition, by J. Hiibner. London, 8°, 1901. 

FiNKENER. — Ueber die quantitative Bestimmung des Holzschliffes 
in Papier nach Groddefroy und Coulon. 1892. 

Flatters. — Microscopical Eesearch. 1906. 

Griffin, E. B. and Little, A. D. — The Chemistry of Paper-making, 
with Principles of General Chemistry. Neiu York, 8°, 1894. 

Hassak. — "Wandtafeln fiir Warenkunde u. Mikroskopie. 1904. 

Haywood, J. K. — Arsenic in Papers and Fabrics. 1904. (U.S.A. 
Department of Agriculture.) 

Herzberg, W. — Mikrosk. Untersuchung des Papiers. 1887. 

Herzberg, W. — Papierpriifung. Leitf. bei d. TJnters. v. Papier. 
1888. 

Ditto, 2nd edition. 1902. 
Ditto, 3rd edition. 1907. 

Herzberg, W. — Paper Testing as carried out in the Government 
Laboratory at Charlottenburg. From the German, by P. N. Evans, 
London, 8°, 1892. 

Herzberg, W. — Mitteilungen aus den konigl. technischen Ver- 
suchanstalten zu Berlin. 1887, et seq. 

HoHNEL, F. V. — Die Mikroskopie der technisch. verwendeten 
Faserstoffe. 1905. 

HoLBLiNG, V. — Die Fabrikation der Bleichmaterialien. Berlin. 

HoYER, E — Le papier ; etude sur sa composition, analj'ses ot 
essais. De I'Allemand. Parts, 8°, 1884. 

Hoyer-Kraft. — Die Spinnerei, Weberei und Papierfabrikation, 
4 Aufl. 1904. 

Jagenberg, F. — Die theorische Leimung fiir endloses Papier. 
Berlin, 8°, 1878. 

JoHANKSEN. — Mitteilungen uber Mikrophotographic von Faser- 
stoffen im durchfallenden und aufSallenden Licht. 1906. 

Klemm, p. — Papier Industrie Kalendor. 1898, et seq. 

Lauboeck. — tjber die Saugfahigkeit der Loschpapiere. Mitteil- 
ungen des k.k. Technologischen Gewerbe-Museums. Wien, 1897. 

Leach, C. E. — On the Shrinkage of Paper (excerpt). Newcastle, 
8°, 1884. 

Martens, A. — Mitteilungen aus den Konigl. Technischen Ver- 
suchsanstalten (jahrlich). Erscheinen seit 1883. Die Jahrgange 



BIBLIOGEAPHY 255 

1884 bis 1903 enthalten aus der Abteilung fiir Papierpriifung die im 
Jabrgang 1905, dieses Kalenders vei'zeiclineten Arbeiten. 

Maktens, a. — Apparaten zur Untersuchung der Festigkeitseigen- 
scbaften von Papier. Konigl. Techn. Yersuchsanstalten. Mitteil- 
ungen. Erganzungsbeft. No. 3. 8°, 1887. 

Martens, A. — Ueber Druckpapier der Gegenwart. Konigl. Tecbn. 
Versucbsanstalten. Mittheilungen. Erganzungsbeft. No. 4. 8°, 1887. 

Martens, A. — Untersucbung Japaniscber Papiere. KonigL Tecbn. 
Versucbsanstalten. Mittbeilungen. Erganzungsbeft. No. 4. 8°, 1888. 

Martens und GtUTH. — Das koniglicbe Materialpriifungsamt der 
tecbmscben Hocbscbule Berlin auf dem Gelande der Domane Dablem 
beim Babnbof Gross-Licbtei'felde West. Berlin, 1904. 

Melnikoff, N. — Prufung von Papier und Pappe nebst Adressbucb 
der russiscben Papierfabriken. Petersburg, 1906. 

MtJLLER, L.— Die Eabrikation d. Papiers in Sonderbeit d. a. d. 
Mascbine gefertigten. 2 Aufl. 1855. 

MIJLLER UND A. Haussner. — Die Herstellung u. Priifung des 
Papiers. 1905. 

MtJLLER, A. — Qualitative und quantitative Bestimmung des 
Holzscbliffes im Papier. 1887. 

MuTH. Die Leimung der Papierfaser im Hollander und die 
Anfertigung fester Papiere. 1890. 

Naylor, W. — Trades Waste. London, 1902. 

NoRMALPAPiER. — Sammlung der Vorscbriften fiir amtlicbe Papier- 
und Tintenpriifung. Berlin, 1892. 

PiETTE, L. — Traite de la coloration des pates a papier. Precede 
d'un aper9u sur I'etat actuel de la fabrication du papier. Ave"c 
ecbantillons de papiers colores. Paris, 8°, 1863. 

Eejto, a. — Anleitung fur Private zur Durcbfiibrung der Papier- 
priifung. Budapest, 1893. 

EossEL. — Papiere und Papierpriifung mit Beriicksicbtigung der in 
der Scbweiz verwendeten Scbreib-und Druckpapiere. Biel, 1895. 

Schumann, Dr. G. — Welcbe Ursacbe bedingen die Papierqualitat. 
Biberach, 1901. 

SiNDALL, E. W. — Paper Tecbnology. London, 1906. 

Stevens, H. P. — Tbe Paper Mill Cbemist. London, 1907. 

WiESNER, J. — Mikroskopiscbe Untersucbung des Papiers mit 
besonderer Beriicksicbtigung der altesten orientaliscben und europa- 
iscben Papiere. Wien, 1887. 

WlESNER, J. — Mikroskopiscbe Untersucbung alter osturkestaniscber 



256 THE MANUFACTUEE OF PAPEE 

und anderer asiatischer Papiere nebst histologisclien Beitragen zur 
mikroskopisclien Papieruntersuchung. Wien, 1902. 

WiNKLEE, 0. — Die Trockengelialts-Bestimiriung d. Papierstoffe. 
1902. 

Winkler, 0., und Karstens, H. — Papieruntersucliung. 1903. 

WURSTER. — Le collage et la nature du papier. Paris, 1901. 

WuRSTER, Dr. 0. — Die neuen Eeagentien auf Holzschlifl xmd 
verholzte Pflanzenteile zur Bestimmung des Holzschliffs im Papier. 
Berlin. 
. ZiRM, A. — Der Papierfarber. Tilsit, 1904. 

CELLULOSE, ETC 

Beadle, C. — Viscose and Viscoid. Franklin Institute reprint. 
1896. 

Bersch, J. — Cellulose, Oelluloseprodukte u. Kautschuksurrogate. 
1903. 

BocKMANN, F. — Das Celluloid, sein Eobmaterial, Fabrikation, 
Eigenschaften u. tecbniscbe Verwendung. 1880. 2te Aufl. 1894. 

BoRNEMANN, Gr. — Ueber Cellulose and neuere Umwandlungspro- 
dukte derselben. Biherach, 1901. 

Bottler, M. — Die vegetabilischen Faserstoffe — Hartleben's cbem- 
iscbe techniscber Bibliothek. 1900. 

BxjTSCHLi, O. — ^Untersucbgn. an Gerinnungsscbaumen, Spbaro- 
kystallen u. d. Sfcruktur v. Cellulose. 1894. 

Cross, C. F., and Bevan, E. J. — Cellulose. London, 1885. 
2nd edition. 1895. 

Cross and Bevan. — ^Eesearcbes on Cellulose. 1895 — 1900. 
Ditto, 1900—1905. 

Margosches, Dr. B. — Die Viskose, ibre Herstellung, Eigenscbaften 
und Anwendung. Leipzig, 1906. 

Sohlesinger, Kunstliche Seide (Zellstoef-Setde). — Mecba- 
niscbtecbnologiscbe TJntersucbung der aus nitriertem Zellstoffs berge- 
stellten Seide. 1895. 

FIBRES, ETC. 

Andes, L. E. — Die Verarbeitung des Strobes. Wien, 1898. 

Bagshaw. — Pbotomicrograpby. Elementary. 

Bengal Government. — Jute in Bengal, and on Indian Fibres avail- 
able for tbe Manufacture of Paper. Eeport by H. Kerr. Calcutta, 
fob, 1874, 



BIBLIOGRAPHY 257 

Bleekrode, S. — Grondstoffen voor Papierbereiding, bizonder in 
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Bottler, M. — Die animaliscbe Faserstoffe. 1901. 

Carter. — Spinning of Fibres. 1904. 

Oobbett. — A Treatise on Oobbett's Corn. 1828. (Printed on paper 
made of corn husks.) 

Christy. — Commercial Plants and Drugs. 1882. 

Cross and Bevan. — Eeport on Indian Fibres. 1887. 

Cross, C. F. — Eeport on Miscellaneous Fibres. 1886. 

Cross, C. F.— Bast Fibres. Manchester, 1880. 

Dj?5^E]sr, G. — Jute. Manila, Adansonia. 1902. 

D:epierre, J. — Traite des apprets et specialement des tissus de coton, 
blancs, teints et imprimes. 

Dodge, C. E.— Leaf Fibres of tbe United States. 1903. 

Gaboon, Jules. — Bibliograpbie de la tecbnologie cbimique des fibres 
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Gelder Zonen, van. — Een woord over nieuwe Grondstoffen voor 
Papier, mit monsters van ded proeven, etc. Amsterdam, sm. 4°, 
1866. 

Georgievics, G. v. — Lebrbucb der cbemiscben Technologie der 
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Georgievics, G. v. — Lehrbucb d. cbemiscben Tecbnologie d. 
Gespinnstfasern. 2te Tie. 1898—1902. 

Georgievics, G. v. — Technology of Textile Fibres; from tbe 
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Grothe, H. — Die Technologie der Gespinnstfasern. 1876 — 82. 

GooDALE. — Physiological Botany. 1890. 

BEammarsten, 0. — Untersuchungen iiber d. Faserstoffgewinnung, 
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Hannan, W. I. — Textile Fibres of Commerce. 1902. 

HoYER, E. VON. — Die Verarbeitung der Faserstoffe. (Spinnerei, 
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Lecomte, H. — Les textiles vegetaux ; leur examen microchimique. 
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MuLLER, Hugo. — Pflanzenfaser. Leipzig, 1873. 

P. S 



258 THE MANUFACTUEE OF PAPEE 

Payen, a. — Succedanes des chiffons. Paris Universal Exhibition. 
Eapports du Jury International, Classe 7, sect. ii. 8°, 1867. 

PrUHL, E. — Papierstoffgarne, ih.re Herstellung, Eigenschaften u. 
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PosSELT, E. A. — The Structure of Fibres, Tarns, and Fabrics, 
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EosTAiNG AND Othees. — Precis historique, descriptif, analytique 
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EoTJTLEDGE, T. — Bamboo considered as a Pa]Der-making Material, 
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EouTLEDGE, T. — Bamboo and its Treatment. 1879. 

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"WiECK, F. Gr. — Bilder aus Gewerbskunst (aus Tomlinson's " Objects 
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Zetzsche, Die. — Wichtigsten Faserstoffe der europaischen Indus- 
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Zimmebmann, a. — Morphologie und Physiologie der Pflanzenzelle. 

HISTORICAL. 

Blanchet, Augustin. — Essai sur I'histoire du papier et de sa 
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Briquet, C. M. — Bermerkungen tiber das Sammeln von Wasser- 
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Erscheinen gegen 1282 bis 1600. Mit Beigabo von 15500. 1906. 



BIBLIOGRAPHY 259 

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Jenkins, R. — Paper-making in England, 1495, etc., from the 
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s2 



260 THE MANUFACTUEE OF PAPER 

KLEm, A. — EntwickluDg und Aufgaben der Papierindustrie. 
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Ditto, 2nd edition, 1801. 

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Murray, J. — Practical Eemarks on Modern Paper, etc., witb an 
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Paralatore, p. — Memoire sur le papyrus des Anciens et sur le 
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Peignot, E. G.— Essai sur I'bistoire du parcbemin et du velin. 
Paris, 8°, 1812. 

Penig. — (Patentpapierf abrik zu Penig.) Ein Beitrag z. Gescbicbte 
d. papiers, 1897. 

Egbert, N. L. — ^Le centenaire de la macbine a papier continu. Son 



BIBLIOGRAPHY 261 

invention par N. L. Eobert en 1799. Biographie de I'inventeur, par 
J. Breville. Historique des divers perfectionnements . . . par Didot 
Saint-Leger, 1800—1818. Paris, 8°, 1901. 

EoBERTSOisr. — Fifty Years' Experience in Paper-making. Leith. 

ScHAEFFER, J. C. — Proefnemingen en Monster- Bladen om Papier 
te maaken zonder Lumpen of met een gering Byvoegzel derzelven. 
Uit het Hoogduitch. Vertaald. Deel 1 — 2. Amsterdam, 2 vols., sm. 4°, 
1770. 

ScHAEFFER, J. 0. — Samtliche Papierversuche, 2te Aufl. Nebst 
81 Mustern und 13 Kupfertafeln. Regenshurg, 6 vols, in one, sm. 4*^, 
177?. 

SCHAEFFER, J. 0. — Erweis in Musterbogen dass die neuen Papierarten 
. . . sich. allerdings aucb zu Tapeten ubermablen und gebraucben 
lassen. Regenshurg, fol. 

Smith, J. E. A. — History of Paper, Genesis and Eevelations. Holyohe, 
Mass., U.S.A., 1882. 

SoTHEBY, S. L. — The Typography of the lotb Century . . . 
Exemplified in a Collection of Facsimiles from 100 Works, with 
their Watermarks. London, fol. 1845. 

SoTHEBY, S. L. — Principia Typographica. An Attempt to Elucidate 
the Paper Marks of the Period. London, 3 vols., fol. 1858. 

Spechthausek. — Hundert Jahre der Papierfabrik Spechthausen. 
Festschrift, z. 1887. 

Spicer, a. — The Paper Trade. London, 1907. 

Stoppelaar, J. H. DE. — Het Papier in de Nederlanden gedurende 
de middleeuven, inzonderheid in Zeeland. Middlehurg, 8°, 1869. 

ToMMNSON, 0. — Illustrations of the Useful Arts. No. 3, Paper. 
London, 32°, 1859. 

ViLLETTE, 0. Marquis de. — (Euvres, -with Specimens of Paper. 
Londres, 16°, 1786. 

WiLLKOMM, M. — tJber den Lotos und Papyros der alten Agypter und 
die Papiererzeugung in Altertume. Prag, 1892. 

PAPER MANUFACTURE. 

Archer, T. C. — The Manufacture of Paper. Bevan. British 
Manufacturing Industries, viii. Sm. 8°, 1876. 

Arnot.— Technology of the Paper Trade (Cantor Lecture, Society 
of Arts). London, 1877. 

Barse, J. — Etudes comparees sur I'industrie Frangaise, ii. La 



262 THE MANUPACTUEE OF PAPEE 

fabrication et le commerce du papier en 1860 et en 1864. Pm^is, 1. 8°, 
1864. 

Beadle, C. — Paper Manufacture — Lectures. 1901. 

Beadle, 0. — Chapters on Paper -making. Yol. 1. London, 1904. 
Yol. 2, Answers to Teclinological Questions. 1906. 
Yol. 3, Practical Points in Paper Manufacture. 1907. 
Yol. 4, Ditto. 1907. 

Beaumont, P. — Eeport on Apparatus and Processes used in Paper- 
making, etc. Paris Universal Exhibition, 1867. British Commercial 
Eeports, Yol. 4. 8°, 1867. 

Bennett, J. B. — Paper-making Processes and Machinery, with 
Illustrations of Paper-making Machinery constructed by Bertrams, 
Ltd. JEdinburgh, 8°, 1892. 

Berteams, Ltd. — Specimens of Paper. Edinhurgli, obi. 16°, 1892. 

Blanchet, .1.— Eabrication du papier. Eapports, Paris Universal 
Exhibition, 1900. 

Brown, H. T. — The Manufacture of Paper from Wood in the United 
States. 1886. 

BuROT. — Note sur la fabrication du papier de paille. Paris, 8°, 
1883. 

Campredon, E. — Le Papier. Iltude monographique sur la papeterie 
Eran5aise et en particulier sur la papeterie Oharentaise. i. Historical ; 
ii. Descriptive of Modern Paper-making ; iii. Co-operative Paper- 
making. Paris, 8°, 1901. 

Oharpentier, p. — Le Papier. Fremy, E. Encycl. Chim., Tome X. 
8° (83), 1890. 

Clapperton, Q-. — Practical Paper-making. London, sm. 8°, 1894. 
Ditto, 2nd edition, 1907. 

Coney, E. —Paper-making Machinery and Fibres. Philadelphia 
International Exhibition, 1876. U.S.A. Centennial Commission 
Eeports and Awards, Group xiii. 8°, 1876. 

Dalheim, C. F.— Taschenbuch f. d. prakt. Papierfabrikanten. 
3teAufl. 1896. 

Dammer, 0. — Papierfabrikation. 

Davis, C. T.— The Manufacture of Paper. Philadelphia, 8^, 1886. 

DouMERC AND OTHERS. — Material et precedes de la papeterie, etc. 
Paris Univ. Exhibition, 1867. Eapports du Jury International, 
Classe 59. 8°, 1867. 

Doyle, P. — Paper-making in India, being Notes of a Yisit to the 
Lucknow Paper Mill. Lucknow, 8°, 1885. 



BIBLIOGEAPHY 263 

Deopisch, B.— Handb. d. Papierfabrikation. 3e Aufl. 31 Taf. in 
fol. 1881. 

Dunbar, J.— The Practical Papermaker. Leith, 12°, 1881. 

Habtmann, C. — -Handb. d. Papierfabrikation. Taf. 1842. 

Hassak, K. — Die Erzeugung des Papieres. 

Hausneb, a. — Der Hollander. Eine kritiscbe Betracbtung seiner 
Arbeitsweise mit Bezug auf die Einzelabmessungen seiner Teile nnd 
die verarbeiteten Easern. 1901. 

Hebbing, E. — Paper and Paper-making, Ancient and Modern. 
London, 8°, 1854. 

IDitto, 2nd edition, 1855. 
Ditto, 3rd edition, 1863. 

HoFMANisr, 0. — A Practical Treatise on tbe Manufacture of Paper 
in All its Branches. Philadelphia, 4°, 1873. 

HoFMANN, C. — • Praktiscbes Handbucb d. Papierfabrikation. 
1873. 

HoEFMANN, Th. — Papierpragung. Berlin. 

HoYEB, E. — Das Papier, seine Bescbaffenbeit und deren Priifung. 
Munchen, 1882. 

HoTEB, E. — Uber die Entstebung und Bedeutung der Papiernor- 
malien, sowie deren Einfiuss auf die Eabrikation des Papieres. 
Munchen, 1888. 

HoTEB, E. — Die Eabrikation des Papiers. 1900. 

HoYEB, E. — Die Eabrikation des Papiers, nebst Gewinnung d. 
Easern. 1887. 

HiJBNEB, J. — Paper Manufacture (Cantor Lectures to tbe Society of 
Arts). 1903. 

Jagenbebg, P.— Das Hollandergescbirr. Eemscbeid. 1894. 

Kibchneb-Stbohbach. — Hollander-Tbeorie. Biberacb. 1904. 

KiiEMM, Db. p. — tJber Papier. Klimscb's Grapbiscbe Bibliotbek 
Bd. 3 (Farbe und Papier im Druckgewerbe). 2 Teil. Frankfurt 
a. M. 1900. 

KoBSCHiLGEN UND Sellegeb. — Tecbnik und Praxis der Papier- 
fabrikation. Berlin, 1906. 

Kbaft, M. — Grundriss der mecbaniscben Tecbnologie. Abt. ii. 
Spinnerei, Weberei, und Papier-fabrikation. 2te Aufl. Wiesbaden, 
8°, 1895. 

Lenobmand, L. S.— Manuel du fabricant de papier. Paris, 
2 vols., 18°, 1833. 

Ditto, 2nd edition. 1834. 



264 THE MANUFACTURE OF PAPEE 

Lenormand, L. S. — Nouveau manuel complet du . . . fabricant 
de papiers peints. ISTouv. ed. par Yergnand. Paris, 18°, 1854. 

LENOE.MAND, L. S. — Handbuch der gesammten Papier-fabrikation, 
2te Aufl, von 0. Hartmann. Weimar, 2 vols., 12°, 1862. 

Meez. — Bebandlung der Papiermaschine. 

Meynier, H. — Papier und Papier-Fabrikate. Paris Univ. Exhibi- 
tion, 1867. Austrian Comm. BericMe. Heft 8. 8°, 1867. 

Mierzinski, St. — Handbuch d. Papierfabrikation. 3 Bde. 1886. 

Mtjller, F. a. L. — Die Fabrikation des Papiers, in Sonderbeit der 
auf der Mascbinen gefertigten, etc. 3te Aufl. Berlin, 8°, 1862. 

MuLLER, Db. L. — Die Fabrikation des Papiers. Berlin, 1877. 

Olmer, GrEORGES. — Du papier mecanique. 

Onerot. — L'art du papier et le papier d'Arcbes. 1907. 

Paper-Making. — Paper-making, by the Editor of tbe Paper Mills 
Directory, London. 2nd edition. 8°, 1876. 

Paper-Maker. — Tbe Paper-makers' Handbook and Guide to Paper- 
making, by a Practical Paper-maker. London, sm. 8°, 1878. 

Paper-Manufacture. — Essays by a Society of Gentlemen. 
No. vi., pp. 21—27. 1717. 

Parkinson, E. — Treatise on Paper, with Outline of Manufacture. 
1886. 

Ditto, 2nd edition, 1896. 

Payen, a., and others. — La fabrication du papier et du carton. 
3«ed. Pans, 8°, 1881. 

Payen, A., and Yigreux, L. — La papeterie. Etudes sur 1' Exposi- 
tion de 1867. Yol. 8. 8°, 1867. 

Pfau, F. — Der junge Papierbandler. Berlin, 1902. 

Piette, Ij. — Manuel . . . de papeterie et les succedanes (des 
cbiffons). Paris, 2 vols., 8°, 1861. 

Planche, G. — De I'industrie de la papeterie. Paris, 8°, 1853. 

PiiANCHE, G. — Der Papierfabrikation. Bearbeitet von 0. Hart- 
mann. Weimar, 12°, 1853. 

Planche, G.— Bericbt iiber die Eeinigung der Stoffe zur Papier- 
fabrikation. Uebersetzt und vervollstandigt durcb eine chrono- 
logische Skizze der Papier-ErzeugungundderYerbesserungen an den 
Mascbinen zur Eeinigung des Papier-Stofls von A. Eudel. Leipzig, 
8°, 1862. 

Prouteaux, a. — Practical Guide for the Manufacture of Paper and 
(Paper) Boards. With a chapter on Wood Paper in the U.S. by H. T. 
Brown. Philadelphia, 8°, 1866. 



BIBLIOGRAPHY 265 

Peouteaux, a. — Guide de la fabrication du papier et du carton. 
Paris, 12°, 1864. 

Eaab, E. — Die Schreibmaterialen und die gesamte Papierindustrie. 
Hamburg, 1888. 

Eeed, a. E. — Paper Manufacture. Society for the Promotion of 
Scientific Industry. Artisans' Eeports upon the Vienna Exhibition. 
8°, 1873. 

EiCHAEDSON, W. H.^ — The Industrial Eesources of the Tyne . . . 
[Paper]. 1864. 

Schubert, M. — Traite pratique de la fabrication de la cellulose. 
Tra*. p. E. Bibas. Toile. 1893. 

Schubert, M. — Die Praxis der Papierfabrikation mit besond. 
Berucksichtigung der Stolfmischungen und dereu Oalculationen. 
1897. 

Schubert, M. — Die Papierverarbeitung. 2 Bde. 1900 — 1901. 
Bd. 1. Die Kartonnagen Industrie. 
Bd. 11. Die Buntpapierfabrikation. 

SiNDALL, E. W.- - The Manufacture of Paper Pulp in Burma. 
Government Press. Rangoon, 1907. 

SiNDALL, E. W. — The Manufacture of Paper. 1908. Constable 
& Co. London. 

TwERDY, E. — Papier Industrie. Berichte. Wien, 1873. 

Vachon, M. — ^Les arts et les industries du papier. France, 1871 
—1894. 

Vaxenta, E. — Das Papier, seine Herstellung, Eigenschaften, Prii- 
f^ng. 1904. 

Wanderley, G. — Die Papierfabrikation und Papierfabrikanlage. 
Leipzig, 1876. 

Watt, A. — The Art of Paper-making, with the Eecovery of Soda 
from "Waste Liquors. London, sm. 8°, 1890. 

Weber, E. — Paper Industrie. Vienna Universal Exhibition, 1873. 

Wehrs, G. E. — Vom Papier, den vor den Erfindung desselben 
iiblich gewesenen Schreibmassen und sonstigen Schreibmaterialien. 
Halle, 8°, 1789. 
Winkler, O. — Der Papierkenner. 1887. 



PAPER, SPECIAL KINDS. 

Andes, L. E. — Papier- Spezialita ten, praktische Anleitung zur 
Herstellung. 1896. 



266 THE MANUEACTUEE OE PAPEE 

Andes, L. E. — Treatment of Paj)er for Special Purposes. Trans- 
lated from German. 1907. 

Andes, L. E. — Die Eabrikation der Papiermach.e und Papierstoff- 
Waren. Leipzig, 1900. 

Andes, L. E. — Blattmetalle, Bronzen und Metallpapiere, deren 
Herstellung und Anwendung. Wien, sm. 8°, 1902. 

BoECK, J. P. — Die Marmorirkunst fur Buchbindereen, Buntpapier- 
fabriken. Wien, sm. 8°, 1880. 

Briquet, M. — De quelques industries nouvelles dont le papier est 
la base. Geneve, 1885. 

ExNEB, W. E. — Tapeten-und Bunt-papier Industrie. Paris Univ. 
Exhibition, 1867. Austrian Comm. Bericbte. Heft 8. 1867. 

ExNER, W. P. — Tapeten-und Bunt-papier. Vienna Universal 
Exhibition, 1873. Officieller Ausstellungs-Bericbt. Heft 53. 8°, 
1873. 

EiCHTENBERG. — Nouveau manuel complet du f abricant de papiers de 
fantaisie, papiers marbres, etc. Paris, 18°, 1852. 

Hebring, E. — Guide to Varieties and Value of Paper. 1860. 

HoFMANN, A. W. — Eeport on Vegetable Parchment (Gaine's Patent, 
No. 2834 of 1853). London, 8°, 1858. 

Kaeppelin, D. — Fabrication des papiers peints. Lacroix E., Etudes 
sur I'exposition de 1867. Vol. 1. 8°, 1867. 

KaeppeI/IN, D. — Eabrication des papiers peints. 1881. 

LiNDSEY, G. — Pens and Papiermache. Bevan, G. P., Brit. Manu- 
facturing Industries (iii.). 12°, 1876. 

MoKTON, G. H. — The History of Paper-hangings, with Eeview of 
other Modes of Mural Decoration. Liverpool, 8°, 1875. 

Sanborn, K. — Old Time Wall Papers. 1905. 

Schmidt, C. H. — Die Benutzung des Papiermache. Weimar, 12°, 
1847. 

Schmidt, C. H. — Die Papier-Tapetenfabrikation. 3te Aufl. Weimar, 
12°, 1856. 

Schmidt, C. H. — The Book of Papiermache and Japanning. London, 
1850. 

Seeman, Th. — Die Tapete, ihre aesthetische Bedeutung u. Techn. 
Darstellung, sowie kurze Beschreibung der Buntpapierfabrik. 1882. 

SiLCOX. — Manxrfacture of Paj)er Barrels. Vienna Exhibition, 1873. 
U.S.A. Eeports, ii. 

Smee, a. — Eeport on Vegetable Parchment (Gaine's Patent, No. 2834 
of 1853). London, 8°, 1858. 



BIBLIOGEAPHY 267 

Thon, 0. F. G. — Der Fabrikant bunter Papier, 3te Aufl. Weimar, 
12°, 1844. 

Weichelt, a. — Buntpapier Fabrikation. Berlin, 8°, 1903. 

Whiting Paper Co. — How Paper is Made. Holyohe, Mass., 32°, 
1893. 

WlKZEE, A. — Die Bereitung und. BenutzuBg der Papiermache und 
abnlicber Kompositionen, 3te Aufl. Weimar, 12°, 1884. 
Ditto, 4th. edition, 1907. 

"WoOLNOUGH, C. W. — The Wbole Art of Marbling, as applied to 
Paper, Book Edges, etc. London, 8°, 1881. 

W"fATT, SiK M. D. — Eeport on Paper-bangings. Paris Univ. 
Exhibition, 1867. Brit. Comm. Eeport, Vol. II. 8°, 1867. 

STATISTICS AND VARIOUS. 

Akesson. — Lexikon der Papier-Industrie. Deutscb-Engliscb- 
Franzosiscb, 2te Aufl. 1905. 

Archer, T. 0. — -Bntisb Manufacturing Industries. Yol. 15. 
Industrial Statistics. London. 

Earth, E. — Arbeitsregeln fur Fabriken mit besonderer Berucksich- 
tigung von Papier-fabriken. Karlsruhe, 1897. 

Baudisch, J. — Einige ins Papierfacb scMagende Berecbnungen. 
Biberacb. 1893. 

Dyson. — Mosely Commission Eeport. Manchester, 1903. 

Ermel. — Eapport sur le materiel et les precedes de la papeterie, etc. 
Paris Univ. Exhibition, 1878. Eapports. Class 60. 8°, 1881. 

Foreign Oefice, No. 4 (1871). — Eeports on the Manufacture of 
Paper in Japan. London, fob, 1871. 

Geyer, a. — Eegistry of Water-marks and Trade-marks. Compiled 
from the American Paper Trade (2nd edition). Neiu York, 1898. 
Ditto, 5th edition, 1903. 

Gratiot, A. — Description de la papeterie d'Essonnes, London 
International Exhibition of 1851, Prospectuses of Exhibitors. Yol. 2. 
8°, 1851. 

Krawany, F. — Warte der Papier-Halbstofl-und Pappenfabriken 
Oesterreicb-Ungarns. 1905. 

Landgrae, J. — Papier-Holzschliff und seine Zollpolitische Wurdi- 
gung. Mannheim. 

LocKWOOD & Co. — American Dictionary of Printing and Book- 
binding. New York, 1895. 



268 THE MANUFACTUEE OE PAPEE 

Ltjdwig, G. — Trockengelialts-Tabellen. Pima, 1897. 

MacNatjghton, J. — Factory Book-keeping for Paper Mills. 
1900. 

Mahelen. — Papierfabrikation, im Konigr. Wurttemburg (im Jabre 
1860). Stuttgart, 8°, 1861. 

Mark, D. — Kosten der Betriebskrafte bei 1 — 24 stiindiger Arbeitszeit 
taglich imd unter Beriicksicbtigung des Aufwandes f iir die Heizung. 
Munclien u. Berlin. 

Melnikofp, N.— ^Lebrbucb der Papier-Holzscbliff, Zellstoff und 
Pappenfabrikation. Fetershurg, 1905. 

Melnikofp, N. — Kleines bandbucb Papierfabrikation. Fetershurg, 
1906. 

Meli^ikoff, N. — Grescbicbte, Statistik u. Literatur der paper- 
industrie nebst russiscben Wasserzeicben. Fetershurg, 1906. 

Mtjnsell, J. — Obronology of Paper-making. Albany, 8°, 1857. 
Ditto, 4tb edition, 1870. 

MuNSELL, J. — Obronology of tbe Origin and Progress of Paper and 
Paper-making. Albany, 1876. 

MuNSELL, J. — Observations Illustrative of tbe Operation of tbe 
Duties on Paper. London, 8°, 1836. 

MuNSELL, J. — Materiel et procedes de la papeterie, etc., 1889. 
Eapports du Jury. Class 58. 8°, 1889. 

Paris Univ. Exhibition. — Papiers points, 1889. Ea.pports du Jury. 
Classe 21. 8°, 1891. 

Passerat, a. L. — Bareme complet pour papeteries. Paris. 

Patents. — Patent Abridgments. Class 96. Patent Office Abstracts 
on Paper-making. From 1855 to date. 

EouLHAC. — Papeterie. Paris Univ. Exbibition, 1867. Eapports du 
Jury. Classe 7, sect. 1. 8°, 1868. 

Sampson, J. T. — Paper-staining. Mansion House Committee. 
Artisans' Eeports, Parish Exbibition. 8°, 1889. 

Treasury. — Eeport of tbe Excise Commission. 1835. 

YoGEii, K. — Papier-industrie, etc., Auf der Weltausstellung in 
Chicago. Chicago Exhibition, 1893. Austrian Central Committee. 
Officieller Bericbt. Heft iv. 8°, 1894. 

VoiGT, Gr. — Papiergewichtstabellen. Merseburg, ]894. 

Ward, Sir W. — Eeport on German Paper-making Industry. 
Parliamentary Paper, 1905. 

"Water-marks. — Water-marks and Trade-marks Eegistry (2nd ed.). 
New York, 16°, 1898. 



BTBLIOG-EAPHT 269 

WOOD PULP AND PULP WOOD. 

Beitish and Colonial Peinter. — History of Wood Pulp. Vol. 8. 
1882. 

Dttnbae.- — ^Wood Pulp and Wood Pulp Papers. 

ElTTicA, Dr. F. — Geschiclite der Sulfitzellstoff-fabrikation. Leipzig, 
1901. 

FiTTiCA, Dr. F. — Forestry and Forest Products. [Edinburgh 
Forestry Exhibition. 1884.] 

GoTTSTEiN. — HolzzellstofS in seiner Anwendung fur die Papier und 
TextiT- Industrie und die bei seiner Herstellung entstehenden Abwasser. 
1904. 

GrEiFPiN, M. L. — Sulphite Processes. American Society 0. E. 417. 
1889. 

Haepee, W. — ^Utilisation of Wood Waste by Distillation. U.S.A., 
1907. 

Harpe, a. — Die Erzeugung von Holzschlifl und Zellstoff. Wien, 
1901. 

Harpe, A. — -Fliissiges Schwefeldioxyd. Stuttgart, 1901. 

Hubbard. — Utilisation of Wood Waste. 1902. 

Johnson, Gt.— Wood Pulp of Canada. 1902—08. Yearly. 

MiCHAELis, 0. E. — Lime Sulphite Fibre Manufacture in the United 
States. With Eemarks on the Chemistry of the Processes, by M. L. 
Griffin (excerpt). Neiu York, 8°, 1889. 

Phillips, S. C— Uses of Wood Pulp. 1904. 

EosENHEiM, G. M. — Die Holzcellulose. Berlin, 1878. 

ScHUBEET, M. — Die Holzstoff oder Holzschliff-fabrikation. 1898. 

ScHTTBEET, M. — Die Cellulosefabrikation (Zellstoff-fabrikation). 
Praktisches Handbuch fur Papier-u. Cellulose-techniker. 1906. 

SiNDALL, E. W.— The Sampling of Wood Pulp. London, 8°, 1901. 

Veitch, L. p. — Chemical Methods for Utilising Wood. U.S.A. 
Department of Agriculture, 1907. 

Veitch, L. P. — Wood Pulp, Uses of. U.S.A. Consular Eeports, 
vol. xix. 

Banks and Ceate. — Pulpwood Problems. Letters to the Globe, 
Toronto, Canada. 1907. 

Gamble, J. — Indian Timbers. 

Geaves. — The Woodsman's Handbook. U.S.A. 

PiNCHOTT, G. — Forestry Primer. U.S.A., 1900. 



270 THE MANUFACTUEE OF PAPEE 

PiNCHOTT, G. — The Adirondack Spruce. U.S.A. 

Eatteay, J., AND Mill, H. E. — Forestry and Forestry Products. 

Edinburgh, 1885. 

ScHLlCH. — Forestry Manual. 

Some more or less interesting articles on " Paper " will 
be found in the following encyclopsedias, etc. : — 

DATE. 

1738. Chambers's Encyclopgedia. 

1757. Barrow. Dictionary of Arts. 

1759. New. Universal History of Arts. 

1770. Eoyal Dictionary of Arts. 

1788. Howard. A Eoyal Encyclopsedia. 

1806. Gregory. A Dictionary of Arts and Sciences. 

1 807. Encyclopsedia Perthensis. 

1809. Nicholson. The British Encyclopsedia. 

1813. Martin. Circle of the Mechanical Arts. 

1813. Pantologia. 

1819. Eees' Cyclopsedia. 

1821 . Encyclopaedia Londoniensis. 

1827. Jamieson's Dictionary. 

1828. Oxford Encyclopsedia. 

1829. The London Encyclopsedia. 

1830. Edinburgh Encyclopsedia. 
1833. Phillip's Dictionary of Arts. 

1835. Partington. British Cyclopaedia. 

1836. Archseologia, vol. xxvi. 

1836. Barlow. Encyclopsedia of Arts. 

1840. The Penny Encyclopsedia. 

1845. Encyclopsedia Metropolitana. 

1848. Useful Arts of Great Britain. S.P.C.K 

1851. Knight's Cyclopsedia of Industry. 

1855. Appleton's Dictionary of Mechanics. 

1860. Hebert. Mechanic's Encyclopsedia. 

1861. Knight's English Cyclopsedia. 
1861. New American Cyclopsedia. 
1866. Tomlinson's Dictionary of Arts. 

1871. Yeats. The Technical History of Commerce. 

1874. Clarke's Practical Magazine. 

1875. lire's Dictionary of Arts. 



BIBLIOGEAPHT 271 

1875. Globe Cyclopaedia. 

1876. American Meclianical Dictionary. 

1877. Johnson's Universal Cyclopaedia. 
1880. Wylde. Industries of the World. 
1882. Spon's Encyclopaedia of Manufactures. 
1886. Encyclopaedia Britannica. 

1889. Chambers's Encyclopaedia. 

1889. Blaikie. Modern Cyclopaedia. 

1890. Popular Encyclopaedia. 
1892. Spon's Workshop Eeceipts. 

1903* Grilman. International Encyclopaedia. 

1904. Encyclopaedia Americana. 

1904. Tweney's Technological Dictionary. 

Newspapers. 
England. 
Papermaker and British Paper Trade Journal. S. C. Phillips, 
London. 

Papermakers' Circular. Dean & Son, London. 

Papermakers' Monthly Journal. Marchant, Singer & Co., London. 

Paper Box and Bag Maker. S. C. Phillips, Loudon. 

Papermaking. London. 

The Paper and Printing Trades' Journal. London, 

World's Paper Trade Eeview. W. J. Stonhill, London. 

Canada. 
Pulp and Paper Magazine. Biggar- Wilson, Ltd., Toronto. 

United States of America. 
American Bookmaker. Howard Lockwood & Co., New York. 
The Paper Trade. Chicago. 

The Stationer. Howard Lockwood & Co., New York. 
Paper Mill and Wood Pulp News. L. D. Post & Co., New York. 
Paper Trade Journal. Howard Lockwood & Co., New York. 
The Paper World. C. W. Bryan & Co., Holyoke, Mass. 

France. 
Bulletin Journal des Eabricants de Papier. Paris. 
Journal des Papetiers. M. Edmond Eousset, Paris. 
Le Moniteur de la Papeterie Fran9aise. Paris. 



272 THE MANUFACTUEE OF PAPEE 

La Papeterie. Paris. 

La Eevue de la Papeterie Frangaise et Etrangere. M. Edmond 
Eousset, Paris. 

Le Papier. H. Everling, Paris. 

Germany. 

Centralblatt fur die Osterreicliiscli Ungarisclie Papierindustrie. 
Adolf Hladufka, Wien. 

Der Papierfabrikant. Otto Eisner, Berlin. 

Der Papier Markt. Carl Dobler, Frankfurt a. Main. 

Deutscbe Papier und Scbreibwarenzeitung. S. Eicbter, Berlin. 

Die Postkarte. Gustav Fabrig, Leipzig. 

Export- Journal. Gr. Hedeler, Leipzig. 

Holzstofl-Zeitung. Camillo Dracbe, Dresden. 

Papierbandler Zeitung fur Osterreicbungarn. Wien. 

Papier-Industrie. Berlin. 

Papier-und Scbreibwaren-Zeitung. Wien. 

Papier-Zeitung. 0. Hofmann, Berlin. 

Scbweizer Grapbiscber Central- Anzeiger. H. Keller, Luzern. 

Wocbenblatt fiir Papierfabrikation. Guntter-Staib Biberacb 
(Wurtt). 

Wocbenscbrift fur den Papier-und Scbreibwarenbandel. Dr. H. 
Hirscbberg, Berlin. 



BIBLIOGEAPHY 272a 



ANALYSIS, TECHNOLOGY. 

Beadle and Stevens. — Blotting paper, nature of absorbency. 
1905. 

Winkler. — Estimation of Moisture in Y/ood-pulp. 1902. Trans- 
lated by Dr. H. P. Stevens. 

HAUPTVERSAMMLUNa. — Published annually by tbe Verein der 
ZeUsloE und Papier- Ohemiker. Berlin, 1907 et. 

FIBRES, etc. 

Dodge, C. E. — Catalogue of useful Fibre-plants of tbe World. 
Report No. 9. Dept. of Agriculture. 27. S.. 4., 1897. 

Duchesne, E. A. — Repertoire des plantes utiles et des plantes 
veneneuses du globe, etc. Bruxelles, 1846. 

Gabalde, B. — Essai sur le bananier et ses applications a la fabrica- 
tion de papier. 1843. 

MoNTESsus DE Ballore. — Alfa et papier d'Alfa. 1908. 

Pecheux. — Les textiles, les tissus, le papier. 6 pp. Paris, 1907. 

Eenouard. — Etudes sur les fibres textiles. Paris. 

Eenouard. — Les fibres textiles de I'Algerie. Paris. 

EiviERE, AuGUSTE ET Charles. — ■ " Les Bambous." Societe 
d'Acclimatation. Paris. 

ElCHMOND, G. F. — Pbilippine Fibres and Fibrous Substances. 
Manila, Bureau of Printing, 1906. 

HISTORICAL. 

Briquet, C. M. — Eecbercbes sur les premiers Papiers employes du 
X« au XIV'^ siecle. pp. 77. Paris, 1886. 

Briquet, C. M. — De la valeur des Filigranes du Papier comme 
moyen de determiner I'age de documents, pp. 13. Geneve, 1892. 

Briquet, C. M. — La Legende paleographique du Papier de Coton. 
pp. 18. Geneve, 1884. 

Briquet, C. M. — Lettre sur les Papiers usites en Sicile a I'occasion 
de deux maniisci'its en papier dit le coton. 16 pp. Palermo, 1892. 

Desmarest, N. — Art de la Papeterie. Paris, 1879. 

Delon, C. — Hietoire d'un livre. Paris, 1879. 



272b the MANUFAOTUEE OP PAPER 

DiDOT, A. p. — Le centenaire de la Machine a Papier continu. 
pp. 79. Paris, 1900. 

DlciaNSON, J.— Dickinson's Paper Mills. Calcutta, 1884. 

GiRARD, A. — Le Papier ses ancetres ; son Hstoire. Lille, 1892. 

JuLiEN, S. — Description des procedes chinois pour la fabrication 
du j)apier. Traduit de I'ouvrage chinois par Thien-Kong-Kha-We. 
1840. 

Kay, J. — Paper, its history, pp.100. London, 3 893. 

Lempertz, H. — Beitrage zur Greschichte des Leinens Papiers. 
Koln, 1891. 

PAPER MANUFACTURE. 

BoRY, P. — Les Metamorphoses d'un Chiffon. Abbeville, 1897. 

Ohabrol, L. — -La Reglementation du Travail dans I'mdustrie du 
papier, pp. 168. Farts, 1901. 

Demuth, p. — Die Papier Fabrikation. 1903. 

Demuth, F. — Die Storungen in deutschen Wirtschaftsleben 1900. 
Leipzig, 1903. 

LiMOGE. — Cercles d'fitudes commerciales, Le Papier, pp. 140. 
Limofje, 1892. 

PAPER, SPECIAL KINDS. 

Spalding xsd Hodge. — Printing paj)ers ; a handbook. London, 
1905. 

STATISTICS, etc. 

Beadle, C. — Development of Water-marking. London, 1906 
(Society of Arts). 

Dumercy. — Bibliographie de la Papeterie. pp. 28. Bruxelles, 1888, 
Brtjce, H. — Grladstone and Paper Duties. Edinbimjh, 1885. 
Ellis, J. B. — Hints for the Paper Warehouse. Leeds, 1887. 
Webster, J. — Synopsis of Sizes of Paper. Soutlvport, 1889. 
Whitson, W. — The Concise Paper Calculator. Edinhmgh, 1903. 

WOOD PULP, etc. 

Dropisch, B. — Holzstoff et Holzcellulose. Weimar, 1879. 



INDEX 



Ac:^ dyes, 201 

in papers, 239 
size, 170 
Agave, 40 
Alum, 167, 168 
Aniline dyes, 201 

sulphate, 121 
Animal size, 63, 164 
Antichlors, 163 
Art paper, 142 
imitation, 145 
testing, 147 
Asbestos, 174 
Ash in paper, 171 

Backwater, 120, 205 
Bagasse, 41 
Bamboo, 43 
Barker, 97 
Beating engines, 186 
patents, 192. 
power consumed, 191 
Beating, conditions of, 197 

early methods of, 176 
experiments in, 179 
process of, 58, 175 
Bibliography, 253 
Bisulphite of lime, 159 
Bleaching, 57, 83 
powder, 161 
Blue prints, 140 
Board machine, 132, 135 
P. 



Boards, manufacture of, 131 

duplex, 132, 134 
Book papers, quality of, 246 
Books, decay of, 237 
Brown papers, 127 

Carbon-ic acid recorder, 215 
Casein, 165, 235 
Caustic soda, 81, 155 
Cellulose,. 21 

derivatives of, 29 
hydrolysis of, 27, 229 
oxidation of, 28 
percentage of, in plants, 23 
properties of, 26 
Chemical residues in paper, 238 

wood pulp, 104 
Chemicals, 153 
China clay, 117, 150, 171, 204, 

234 
Coal consumption, 214 
Coated paj)er, 142 
Cold ground pulp, 100 
Colophony, 169 

Colour of paper, fading of, 203, 
241 
matching, 205 
unevenness of, 
203 
Colouring of j)aper pulp, 199 

analj^sis of, 206 
Cotton, 22, 69 



274 



INDEX 



Cyanotype papers, 140 
Cylinder machine, 131 

Density of paper, 181 
Deterioration of paper, 228, 246 
Digesters, 52, 89, 109 
Dilution tables, 157, 163 
Duplex boards, 134 
Dyeing of paper, 199 

EiBEL patent, 223 
Electrical power, 219 
Electrolytic bleacbing, 57 
Engine sizing, 117, 167 
Esparto, 72 

bleaching of, 83 

composition of, 73 

test for, in papers, 87 

yield of, 77 
Evaporation apparatus, 76, 79 
tables, 81 

Featherweight papers, 232 

Eibres for paper-making, 38 
examination of, 43 
I'eagents for staining, 71 

Elax, 40 

Eourdrinier machine, early, 16 

French chalk, 173 

Gas producer, 218 
Gelatine, 63, 164, 237 
Glue, 137, 142, 235 
Grinders, 100 

History of paper, 1 
Hoernle, 7 

Hollander, 16, 59, 176, 185 
Hot ground pulp, 100 

Imitation art paper, 145, 235 
Kraft paper, 129 
parchment, 137 



Improvements in paper-making, 

214 
Iron in paper, 229 

Krapt papers, 128 

Laid papers, 66 
Lime, 52, 157 

bisulphite, 159 

sulphate, 173 
Linen fibre, 70 
Loading, 171 

M. G. caps, 130 
Machinery, 214, 224 
Manila paper, 127 
Mechanical pulp, 95 
detection of, 121 
Metanil yellow, 122 
Middles, 134 
Mitscherlich pulp, 107 
Moisture, influence of, 243 
Multiple effect evaporation, 79 

Neutral size, 1 69 
Newsj)aper, 116, 215 

Output of a paper machine, 122 

Paper, art, 142 

ash in, 171 

brown, 127 

bulk of, 231 

chemical residues in, 238 

clay in, 234 

colour of, 199, 241 

colour in, analj'sis of, 207 

deterioration of, 229 

fibres for, 38 

history of, 1, 5 

iron in, 239 

permanence of, 230 



INDEX 



275 



Paper, rags used for, 47 
sizing of, G3 
special kinds of, 137 
standards of quality, 246 
strength of, 184, 231 
surface of, 233 
volume composition of, 
233 

Paper machine, early, 16 

output of, 122 

Papier-mache, 150 

Papyrus, 2, 42 

Paraffin paper, 148 

Parchment, 4 
paper, 137 

Peat, 41 

Phloroglucine, 121 

Pigments, 199 

Porion evaporator, 76 

Presse-pate, 86 

Prussian blue, 200 

Eag- paper, manufacture of, 47 

origin of, 5 
Eags, bleaching, 55 

boiling, 51 

classification, 48 

sorting, 48 
Eamie, 40 
Eecords, early, 1 
Eecovered ash, 158 
Eecovery processes, 78, 113 
Eefiners, 90 
Eoj)e browns, 127 
Eosin size, 117, 169, 236 

Screens, 102 
Sealings, 129 
Shrinkage of paper, 181 
Sizing of paper, 63, 117, 167 
Society of Arts, 246 
Soda, 153 



Soda pulp, 107, 113 

recovery, 78 

silicate of, 166, 171 
Softening of water, 216 
Spent liquors, 78, 113 
Staining reagents for fibres, 71 
Standards of quality, 246, 248, 

250 
Starch, 166, 237 
Stationery Office, 248 
Stone beater rolls, 189 
Straw, 88 
Sulphate pulp, 107 
Sulphite pulp, 107 
Sulphites, 159, 163 
Supercalender, 65 
Superheated steam, 218 

Tinfoil paper, 148 
Transfer j)aper, 149 

Ultramarine, 199 

Volume composition of paper, 

233 
Yulcanised fibre, 139 

Water softening, 216 
Watermarks, 67 
Wavy edges, 243 
Waxed paper, 147 
Wet press machine, 103 
Wiesner, 6 
Willesden paper, 139 
Wood, 22 
pulp, 95 

chemical, 104 

mechanical, 95 

soda, 107, 113 

sulphite, 107 
Wove papers, 66 
Wrappers, 127 



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THE "WESTMINSTER" SERIES 

CoaL By James Tonge, M.I.M.E., F.G.S., etc. (Lecturer 
on Mining at Victoria University, Manchester). With 
46 Illustrations, many of them showing the Fossils found 
in the Coal Measures. 
List of Contents : History. Occurrence. Mode of Formation 
of Coal Seams. Fossils of the Coal Measures. Botany of the 
Coal-Measure Plants. Coalfields of the British Isles. Foreign 
Coalfields. The Classification of Coals. The Valuation of Coal. 
Foreign Coals and their Values. Uses of Coal. The Production 
of Heat from Coal. Waste of Coal. The Preparation of Coal 
for the Market. Coaling Stations of the World. Index. 

This book on a momentous subject is provided for the general 
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and extent, and its economical utilization and application. 

Iron and SteeL By J. H. Stansbie, B.Sc. (Lond), F.I.C. 
With 86 Illustrations. 
List of Contents : Introductory. Iron Ores. Combustible and 
other materials used in Iron and Steel Manufacture. Primitive 
Methods of Iron and Steel Production. Pig Iron and its Manu- 
facture. The Refining of Pig Iron in Small Charges. Crucible 
and Weld Steel. The Bessemer Process. The Open Hearth 
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under the Microscope. Heat Treatment of Iron and Steel. Elec- 
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The aiiTi of this book is to give a comprehensive view of the modern 
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worker may learn the history of the material he is handling. 

Natural Sources of Power. By Robert S. Ball, B.Sc, 
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Contents : Preface. Units with Metric Equivalents and Abbre- 
viations. Length and Distance. Surface and Area. Volumes. 
Weights or Measures. Pressures. Linear Velocities, Angular 
Velocities. Acceleration. Energy. Power. Introductory 
Water Power and Methods of Measuring. Application of Water 
Power to the Propulsion of Machinery. The Hydraulic Turbine. 
Various Types of Turbine. Construction of Water Power Plants. 
Water Power Installations. The Regulation of Turbines. Wind 
Pressure, Velocity, and Methods of Measuring. The Application 
of Wind Power to Industry. The Modern Windmill. Con- 
structional Details. Power of Modern Windmills. Appendices 
A,B,C. Index. 
Two departments of Engineering and their applications to industry 

form the subject of this volume : the " natural " sources of water 

( 2 ) 



THE "WESTMINSTER" SERIES 

and wind power which supply mechanical energy without any inter- 
mediate stage of transformation. Most people will be surprised at 
the extent to which these natural power producers are used. The 
widespread application of water power is generallj^ known, but it is 
interesting to learn that the demand for windmills was never so great 
as it is to-day, and there are signs of abnormal expansion in the direc- 
tion of their useful application in the great agricultural countries of 
the world. Though primarily of importance to the engineer, this work 
will be of great interest to every manufacturer who in economizing 
his means of power production can take the natural forces that lie 
to his hand and harness them in his service. The author is the son 
of Sir Robert Ball, the eminent mathematician and astronomer. 

Liquid and Gaseous Fuels, and the Part they play- 
in Modern Power Production. By Professor 
Vivian B. Lewes, F.I.C, F.C.S., Prof, of Chemistry, 
Royal Naval College, Greenwich. With 54 Illustrations. 

List of Contents : Lavoisier's Discovery of the Nature of Com- 
bustion, etc. The Cycle of Animal and Vegetable Life. Method 
of determining Calorific Value. The Discovery of Petroleum 
in America. Oil Lamps, etc. The History of Coal Gas. Calorific 
Value of Coal Gas and its Constituents. The History of Water 
Gas. Incomplete Combustion. Comparison of the Thermal 
Values of our Fuels, etc. Appendix. Bibliography. Index. 

The subject of this book has, during the last decade, assumed such 
importance that it is hoped this account of the history and develop- 
ment of the use of various forms of combustible liquids and gases 
for the generation of energy may do some service in its advancement. 

Electric Power and Traction. By F. H. Davies. 
A.M.I. E.E. With 66 Illustrations. 

List of Contents : Introduction. The Generation and Distri- 
bution of Power. The Electric Motor. The Application of 
Electric Power. Electric Power in Collieries. Electric Power 
in Engineering Workshops. Electric Power in Textile Factories. 
Electric Power in the Printing Trade. Electric Power at Sea. 
Electric Power on Canals. Electric Traction. The Overhead 
System and Track Work. The Conduit System. The Surface 
Contact System. Car Building and Equipment. Electric Rail- 
ways. Glossary. Index. 

The majority of the allied trades that cluster round the business of 
electrical engineering are connected in some way or other with its power 
and traction branches. To members of such trades and callings, to 
whom some knowledge of applied electrical engineering is desirable 
if not strictly essential, the book is particularly intended to appeal. 
It deals almost entirely with practical matters, and enters to some 
extent into those commercial considerations which in the long run 
must overrule all others. 

( 3 ) 



THE ''WESTMINSTER" SERIES 

Town Gas and its Uses for the Production of 
Light, Heat, and Motive Power. By W. H. Y. 

Webber, C.E. With 71 Illustrations. 

List of Contents : The Nature and Properties of Town Gas. The 
History and Manufacture of Town Gas. The Bye-Products of 
Coal Gas Manufacture. Gas Lights and Lighting. Practical 
Gas Lighting. The Cost of Gas Lighting. Heating and Warm- 
ing by Gas. Cooking by Gas. The Healthfulness and Safety 
of Gas in all its uses. Town Gas for Power Generation, including 
Private Electricity Supply. The Legal Relations of Gas Sup- 
pliers, Consumers, and the Public. Index. 
The " country," as opposed to the " town," has been defined as 
"the parts beyond the gas lamps." This book provides accurate 
knowledge regarding the manufacture and supply of town gas and its 
uses for domestic and industrial purposes. Few people realize the 
extent to which this great industry can be utilized. The author has 
produced a volume which will instruct and interest the generallj^ well 
informed but not technically instructed reader. 

Electro-Metallurgy. By J. B. C. Kershaw, F.I.C. With 
61 Illustrations. 

Contents : Introduction and Historical Survey. Aluminium. 
Production. Details of Processes and Works. Costs. Utiliza- 
tion. Future of the Metal. Bullion and Gold. Silver Refining 
Process. Gold Refining Processes. Gold Extraction Processes. 
Calcium Carbide and Acetylene Gas. The Carbide Furnace and 
Process. Production. Utilization. Carborundum. Details of 
Manufacture. Properties and Uses. Copper. Copper Refin- 
ing. Descrintions of Refineries. Costs. Properties and Utiliza- 
tion. The Elmore and similar Processes. Electrolytic Extrac- 
tion Processes. Electro-Metallurgical Concentration Processes. 
Ferro-alloys. Descriptions of Works. Utilization. Glass and 
Quartz Glass. Graphite. Details of Process. Utilization. Iron 
and Steel. Descriptions of Furnaces and Processes. Yields and 
Costs. Comparative Costs. Lead. The Salom Process. TheBetts 
Refining Process. The Betts Reduction Process. White Lead Pro- 
cesses. Miscellaneous Products. Calcium. Carbon Bisulphide. 
Carbon Tetra-Chloride. Diamantine. Magnesium. Phospliorus. 
Silicon and its Compounds. Nickel. Wet Processes. Dry 
Processes. Sodium. Descriptions of Cells and Processes. Tin. 
Alkaline Processes for Tin Stripping. Acid Processes for Tin 
Stripping. Salt Processes for Tin Stripping. Zinc. Wet Pro- 
cesses. Dry Processes. Electro-Thermal Processes. Electro- 
Galvanizing. Glossary. Name Index. 

The subject of this volume, the branch of metallurgy which deals 
with the extraction and refining of metals by aid of electricity, is 
becoming of great importance. The author gives a brief and clear 
account of the industrial developments of electro-metallurgy, in lan- 
guage that can be understood by those whose acquaintance with either 

( 4 ) 



THE "WESTMINSTER" SERIES 



chemical or electrical science may be but slight. It is a thoroughly- 
practical work descriptive of apparatus and pi^ocesses, and commends 
itself to all practical men engaged, in metallurgical operations, as well 
as to business men, financiers, and investors. 

Radio-Telegraphy. By C. C. F. Monckton, M.I.E.E. 
With 173 Diagrams and Illustrations. 

Contents : Preface. Electric Phenomena. Electric Vibrations. 
Electro-Magnetic Waves. Modified Hertz Waves used in Radio- 
Telegraphy. Apparatus used for Charging the Oscillator. The 
Electric Oscillator : Methods of Arrangement, Practical Details. 
• The Receiver : Methods of Arrangement, The Detecting Ap- 
paratus, and other details. Measurements in Radio-Telegraphy. 
The Experimental Station at Elmers End : Lodge-Muirhead 
System. Radio - Telegraph Station at Nauen : Telefunken 
System. Station at Lyngby : Poulsen System. The Lodge- 
Muirhead System, the Marconi System, Telefunken System, and 
Poulsen System. Portable Stations. Radio-Telephony. Ap- 
pendices : The Morse Alphabet. Electrical Units used in this 
Book. International Control of Radio-Telegraphy. Index. 

The startling discovery twelve years ago of what is popularly known 
as Wireless Telegraphy has received many no less startling additions 
since then. The official name now given to this branch of electrical 
practice is Radio-Telegraphy. The subject has now reached a thor- 
oughly practicable stage, and this book presents it in clear, concise 
form. The various services for which Radio-Telegraphy is or may 
be used are indicated by the author. Every stage of the subject is 
illustrated by diagrams or photographs of apparatus, so that, while 
an elementary knowledge of electricity is presupposed, the bearings 
of the subject can be grasped by every reader. No subject is fraught 
with so many possibilities of development for the future relationships 
of the peoples of the world. 

India-Rubber and its Manufacture, with Chapters 
on Gutta-Percha and Balata. By H. L. Terry, 
F.I.C., Assoc.Inst.M.M. With Illustrations. 

List of Contents : Preface. Introduction : Historical and 
General. Raw Rubber. Botanical Origin. Tapping the Trees. 
Coagulation. Principal Raw Rubbers of Commerce. Pseudo- 
Rubbers. Congo Rubber. General Considerations. Chemical 
and Physical Properties. Vulcanization. India-rubber Planta- 
tions. India-rubber Substitutes. Reclaimed Rubber. Washing 
and Drying of Raw Rubber. Compounding of Rubber. Rubber 
Solvents and their Recovery. Rubber Solution. Fine Cut Sheet 
and Articles made therefrom. Elastic Thread. Mechanical 
Rubber Goods. Sundry Rubber Articles. India-rubber Proofed 
Textures. Tyres. India-rubber Boots and Shoes. Rubber for 
Insulated Wires. Vulcanite Contracts for India-rubber Goods. 



THE "WESTMINSTER" SERIES 

The Testing of Rubber Goods. Gutta-Perclia. Balata. Biblio- 
graphy. Index. 

Tells all about a material which has grown immensely in com- 
mercial importance in recent years. It has been expressly written 
for the general reader and for the technologist in other branches of 
industry. 

Glass Manufacture. By Walter Rosenhain, Superin- 
tendent of the Department of Metallurgy in the National 
Physical Laboratory, late Scientific Adviser in the Glass 
Works of Messrs. Chance Bros, and Co. With Illustra- 
tions. 

Contents: Preface. Definitions. Physical and Chemical Qualities. 
Mechanical, Thermal, and Electrical Properties. Transparency 
and Colour. Raw materials of manufacture. Crucibles and 
Furnaces for Fusion. Process of Fusion. Processes used in 
Working of Glass. Bottle. Blown and Pressed. Rolled or 
Plate. Sheet and Crown. Coloured. Optical Glass : Nature 
and Properties, Manufacture. Miscellaneous Products. Ap- 
pendix. Bibliography of Glass Manufacture. Index. 

This volume is for users of glass, and makes no claim to be an ade- 
quate guide or help to those engaged in glass manufacture itself. For 
this reason the account of manufacturing processes has been kept 
as non-technical as possible. In describing each process the object 
in view has been to give an insight into the rationale of each step, so 
far as it is known or understood, from the point of view of principles 
and methods rather than as mere rule of thumb description of manu- 
facturing manipulations. The processes described are, with the 
exception of those described as obsolete, to the author's definite know- 
ledge, in commercial use at the present time. 

Precious Stones. By W. Goodchild, M.B., B.Ch. With 
42 Illustrations. With a Chiapter on Artificial 
Stones. By Robert Dykes. 

List of Contents : Introductory and Historical. Genesis of 
Precious Stones. Physical Properties. The Cutting and Polish- 
ing of Gems. Imitation Gems and the Artificial Production of 
Precious Stones. The Diamond. Fluor Spar and the Forms of 
Silica. Corundum, including Ruby and Sapphire. Spinel and 
Chrysoberyl. The Carbonates and the Felspars. The Pyroxene 
and Amphibole Groups. Beryl, Cordierite, Lapis Lazuli and the 
Garnets. Olivine, Topaz, Tourmaline and other Silicates. Phos- 
phates, Sulphates, and Carbon Compounds. 

An admirable guide to a fascinating subject. 

( 6 ) 



THE "WESTMINSTER" SERIES 

Patents^ Designs and Trade Marks : The Law 
and Commercial Usage. By Kenneth R. Swan, 
B.A. (Oxon.), of the Inner Temple, Barrister-at-Law. 

Contents : Table of Cases Cited — Part I. — Letters Patent. Intro- 
duction. General. Historical. I., II., III. Invention, Novelty, 
Subject Matter, and Utility the Essentials of Patentable Invention. 
IV. Specification. V. Construction of Specification. VI. Who 
May Apply for a Patent. VII. Application and Grant. VIII. 
Opposition. IX. Patent Rights. Legal Value. Commercial 
Value. X. Amendment. XI. Infringement of Patent. XII. 
Action for Infringement. XIII. Action to Restrain Threats. 
XIV. Negotiation of Patents by Sale and Licence. XV. Limita- 
tions on Patent Right. XVI. Revocation. XVII. Prolonga- 
tion. XVIII. Miscellaneous. XIX. Foreign Patents. XX. 
Foreign Patent Laws : United States of America. Germany. 
France. Table of Cost, etc., of Foreign Patents. Appendix A. — 

I. Table of Forms and Fees. 2. Cost of Obtaining a British 
Patent. 3. Convention Countries. Part II. — Copyright in 
Design. Introduction. I. Registrable Designs. II. Registra- 
tion. III. Marking. IV. Infringement. Appendix B. — i. 
Table of Forms and Fees. 2. Classification of Goods. Part 
III. — Trade Marks. Introduction. I. Meaning of Trade Mark. 

II. Qualification for Registration. III. Restrictions on Regis- 
tration. IV. Registration. V. Effect of Registration. VI. 
Miscellaneous. Appendix C. — Table of Forms and Fees. Indices. 
I. Patents. 2. Designs. 3. Trade Marks. 

This is the first book on the subject since the New Patents Act. 
Its aim is not only to present the existing law accurately and as fully 
as possible, but also to cast it in a form readily comprehensible to the 
layman unfamiliar with legal phraseology. It will be Of value to those 
engaged in trades and industries where a knowledge of the patenting 
of inventions and the registration of trade marks is important. Full 
information is given regarding patents in foreign countries. 

The Book; Its History and Development. By 

Cyril Davenport, V.D., F.S.A. With 7 Plates and 
126 Figures in the text. 

List of Contents : Early Records. Rolls, Books and Book 
bindings. Paper. Printing. Illustrations. Miscellanea. 

Leathers. The Ornamentation of Leather Bookbindings without 
Gold. The Ornamentation of Leather Bookbindings with Gold, 
Bibliography. Index. 

The romance of the Book and its development from the rude inscrip- 
tions on stone to the magnificent de Luxe tomes of to-day have 
never been so excellently discoursed upon as in this volume. The 
history of the Book is the history of the preservation of human thought. 
This work should be in the possession of evey book lover. 

( 7 ) 



Van Nostrand's "Westminster ' Series 



LIST OF NEW AND FORTHCOMING 
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Timber. By J. R. Baterden, A.MT.C.E. 
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A.M.I.M.E. 

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A.M.I.E.E. 

The Railway Locomotive. By Vaughan Pendred, 

M.I.Mech.E. 

Leather. By H. Garner Bennett. 

Pumps and Pumping Machinery. By James W. 

RossiTER, A.M.I.M.E. 

Workshop Practice. By Professor G. F. Char- 
nock, A.M.I.C.E., M.I.M.E. 

Textiles and their Manufacture. By Aldred Bar- 
ker, M.Sc. 

Gold and Precious Metals. By Thomas K. Rose, 

D.Sc, of the Royal Mint. 

Photography. By Alfred Watkins, Past Presi- 
dent of the Photographic Convention. 

Commercial Paints and Painting. By A. S. Jen- 
nings, Hon. Consuhing Examiner, City and Guilds of 
London Institute. 

Ornamental Window Glass Work. By A. L. 

DUTHIE. 

Brewing and Distilling. By James Grant, F.C.S. 
Wood Pulp and Its Applications. By C. F. Cross, 

E. J. Bevan and R. W. Sindall. 

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